Holy cow, you're having a lot of issues, so let's begin...
1: You'll need to train yourself to only sleep on your back with your upper body elevated slightly so contents flow to the bottom of the bag. You can do this by using pillows under each arm and some pillows behind your chest and head. Lying on your left or right side causes problems because the belt is either pulling or the body is causing the wafer to detach. Obviously, lying on your belly causes pressure issues.
2: Pancaking and ballooning are caused by diet, which you can control. I'll post my list at the bottom of this post. You don't need to poke holes in your bag. Simply sit on the toilet and dump, then gently press the bag to let extra air out, but you don't want it completely flat as a vacuum also causes pancaking.
3: You need to take the Coloplast test to see what appliance is appropriate for you.
https://www.coloplast.us/global/ostomy/ostomy-self-assessment-tools/
I suggest you start with a one-piece (bag and wafer combined) instead of a two-piece (bag clicks on) as this is more secure. If you do things right, you'll see a two-piece system is nearly useless for an ileostomy because your wafer will last as long as the bag (about 4-7 days) and just change both at the same time.
4: Showering. Unfortunately, you'll have to forsake hot showers while the bag is on because your body will simply sweat it off. So take lukewarm showers and don't direct water onto the bag. Use a washcloth to wash your chest instead. I put some waterproof tape along the top edge of my extra-large barrier strips just in case. The bag may get wet regardless, but blow drying works to dry it out. For the Coloplast belt, simply use small trash bags unfolded to tuck under the belt; however, NEVER lift the belt as that will cause wafer separation. I only remove my belt if I'm going to do a bag change. Make sure the belt isn't too tight or too loose, just snug.
5: Belly button, I simply fill the hole with a little wad of toilet paper to level, then cover with a 1/4 cut extra-large barrier strip piece to give it strength. It will then be partially covered by the wafer flange and the full exterior barrier strip later. Combined with a belt, this cures the belly button weakness issue. However, NOT if you're sleeping on your left side.
6: Pancaking caused by vacuum. When you dump, use a couple of drops of liquid antibacterial dish soap followed by a water bottle and wash your bag right there on the toilet followed by a couple of rinses. Then use a long plastic stick or something to insert into the bag and separate the two pieces of plastic bag, then a drop of the antibacterial dish soap and a little water, then seal. Then roll the bag up some and force the extra air near the top of the bag. The bottom of the bag will cling and trap the air near the top of the bag. If you have a pancaking issue caused by diet, the stool is thick coming out, you train yourself to look and feel for this occurring BEFORE the bubble starts forming. Then use the method above to wash, rinse, then add water and seal, go lay on your back and gently massage the pancaking loose. Don't squeeze the bag or try to physically push the pancaking output loose; these can cause a seal to leak just like pancaking or ballooning putting sideways pressure on the seal. Once you control your diet, you'll learn what to eat to avoid pancaking and ballooning issues most of the time.
7: Acid issues. Coffee is the #1 cause of leak burns being far worse than normal. The body considers it a poison and is flushing it out along with coffee acid and stomach acid with very low pH levels. However, normally your intestine pH level is about 8. Any caffeine is going to cause diarrhea issues where the stoma just keeps spewing. If you switch to tea, the burns will be less intense; however, diarrhea will occur, which if you have a good bag on, then it doesn't matter; you just wait it out. However, if you're still learning and having leak issues, then it's best to avoid caffeine until you do get good bags on consistently. Because a spewing stoma is about impossible to get a good dry seal going. You may have to wait in the shower for hours until it does calm down.
8: Without a picture of your stoma, it's difficult to ascertain if you need a ring or paste. Usually, if the skin is flat, clear, level, and without wounds, and the stoma sticks out well, then a ring will work. However, if anything else, then paste usually works better, but it's trickier. However, when you wash around the stoma, I use only antibacterial soap or regular soap without lotions, oils, etc. (or from runoff from shampoo) as that residue will cause a bag to detach prematurely. Skin required to be clean, dry, dust-free, and oil-free (like from spew), and if not, then you head to the shower to clean it and blow dry the skin thoroughly until you can feel the skin isn't slippery anymore. I use paste because I can apply it to wounds with a thin coat around the stoma 1/2" to see if it's going to stick first, remove and discard if it doesn't. Blow dry and try again until it does stick. This way, I'm not wasting an expensive ring or a wafer. The antibacterial soap also causes burn wounds to dry out some, killing the digestive enzymes eating the skin and causing weeping issues which makes adhesion impossible. However, with paste, it might be necessary to mix in a little stoma powder first before applying to get it to set faster. Paste can also run down, so lying on one's back for a while may be required until it does set up; also, delay putting the belt on until it does because the belt will squeeze the paste out more than you want. Also, with a one-piece, you have to make sure paste doesn't cover the stoma, or that will cause a clog. If that accidentally occurs, I just stick my stick up there and scrape it loose. Otherwise, I put the paste about 1/3" away from the stoma, mix in a little bit of stoma powder, and press down so the flange sticks, and usually, the paste goes right to the edge of the wafer hole. It doesn't have to go right up to the stoma because I applied the thin paste coat earlier. This two-step process is necessary for me as I have a near flush stoma in a belly fold. Which I have to horizontally weaken the convex wafer bubble so it's more flexible and curved so it bends when I bend. I use paste because I can control the adhesive strength if needed. So without seeing your clear stoma, I can see which would be better for you. But any dips, bumps, wounds, etc. usually paste is better than a ring. You don't want spew getting underneath to reach your skin.
Okay, with that, I'll give you my copy and paste info. It's a lot, sorry, I'm very thorough. 😁
I do drink plenty of water and an electrolyte drink occasionally. I ensure I'm urinating and it's a normal yellow or clear, not dark orange or dry, which would indicate dehydration.
Coffee can make output very acidic, making the burns far worse. Caffeine can cause diarrhea where the stoma just keeps spewing for hours. Dried Chinese Crispy Noodles, Cheerios, or applesauce (peeled apples) or bananas are the exact opposite, a stool-thickening food. By mixing these with other foods, one can manipulate their stool output and counter the issues above. Also, the severe thickening helps in cases where one has severe diarrhea and is unable to reattach a new bag due to high flow.
Eating Guide
Partially copied from my nutritionist's guide. Ileostomy Nutrition Therapy from the Academy of Nutrition and Dietetics. (This handout may be duplicated for client education.)
My recommendation is to see a nutritionist for the full guide as not all can be pasted here.
I've added my own observations to further clarify
Chew all foods well to the consistency of paste. Spit out any hard stuff. Important!
Foods That May Cause Blockage (very bad, avoid!) and
Apples, unpeeled (peeled and applesauce are excellent thickeners, don't eat the skins or the core, chew well)
Bean sprouts, Cabbage
Casing on sausage (inside fine if no tough parts, avoid swallowing if a chunk is felt) Also, sausage-like meats like pepperoni and salami contain indigestible bits.
Chinese vegetables (stir-fried crunchy, too hard, need very soft veggies with no skins)
Coconut, Coleslaw, Celery (avoid)
Corn (grits also, corn anything doesn't seem to dissolve in the stomach)
Cucumbers (skins bad, inside chewed up good seems okay, no seeds)
Dried fruit, raisins
Grapes, blueberries, etc. (skins and seeds the problem.)
Green peppers (red, yellow also) pureed or very very small and soft seems okay in small amounts
Mushrooms (doesn't dissolve in the stomach) pureed or very very small seems okay in small amounts
Nuts (totally avoid)
Peas (mushy interior okay, like pea soup, skins a problem)
Pickles (skins a problem, inside if chewed up good seems okay, seeds not)
Pineapple (liquid okay, mushy parts fine, hard parts not, rather risky as parts of mushy may not digest)
Popcorn (totally avoid)
Potato skins, inside (no hard parts) fine.
Relishes and olives
Salad greens (diarrhea nightmare too)
Seeds and nuts (avoid)
Spinach (doesn't digest, pureed perhaps)
Tough, fibrous meats (for example, steak on grill, well done, tough parts especially, over-grilled chicken or dry pork chops. Juicy grilled or pan-fried chicken, shredded pork in juices, medium rare steaks, hamburger better. Nothing deep-fried ever, diarrhea city.
Vegetable and fruit skins, (any avoid)
Whole grains (no grits, rolled oats oatmeal seems to be okay, oat cereal is an excellent thickener)
Foods That May Cause Gas or Odor
Alcohol, Apples, Asparagus (stink), Bananas, Beer, Broccoli (clog hazard)
Brussels sprouts (clog hazard)
Cabbage (clog hazard)
Carbonated beverages
Cauliflower, Cheese, some types like cheese food is bad. Real cheese may be okay.
Corn (clog hazard), Cucumber
Dairy products (toot city)
Dried beans and peas (clog hazard)
Eggs (some don't digest in the stomach like scrambled or omelets, but over easy seems fine for some reason)
Fatty foods, Grapes
Fish (cooked unseasoned salmon in small portions may not, nor stink, same for raw tuna seems fine)
Green pepper (red and yellow also, clog hazard unless very small and very soft in small quantities)
Melons, Onions (clog hazard)
Peanuts (clog hazard) Prunes
Radishes, Turnips
Soda and sipping using straws, (drink from glass instead)
Seafood (oh God does it stink!)
If you're having pancaking issues, a small amount of something above (like having a soda during a meal) could introduce some air into your diet and thus into the bag. Also, by avoiding too much thickening foods by themselves which often contribute to pancaking.
Foods That May Help Relieve Gas and Odor
Buttermilk, Cranberry juice, Parsley
Yogurt with active cultures (Greek yogurt)
Foods That May Cause Diarrhea (looser or more frequent stool)
Alcohol (including beer)
Apricots (and stone fruits)
Beans, baked or legumes (clog hazard)
Bran, Broccoli, Brussels sprouts
Cabbage, Caffeinated drinks
Chocolate
Corn (in my experience corn anything doesn't digest in the stomach, just passed through and out, kernels/popcorn will clog)
Deep Fried meats, fish, poultry (KFC, supermarket rotisserie chicken very bad, and anything soaked in brine)
Fruit juice: apple, grape, orange (small amount okay)
Fruit: fresh, canned, or dried (small amount skinless okay)
Glucose-free foods containing mannitol or sorbitol
Gum, sugar-free, Licorice
High-fat foods, High-sugar foods
High salt foods (KFC, supermarket rotisserie chicken)
High seasoned foods (like blackened)
Milk and dairy foods (small amounts okay)
Nuts or seeds (bad, clog hazard)
Peaches (stone fruit, one rarely okay)
Peas, Plums (stone fruit)
Prune juice or prunes
Soup, Spicy foods
Sugar-free substitutes
Tomatoes, Turnip greens/green leafy
Vegetables, raw
Wheat/whole grains, Wine
Rice (very soft 1/4 cup in mixed in food okay), refried beans (1/4 cup okay) pasta (one cup max).
Any foods soaked in brine or deep fried (rotisserie chicken, Kentucky fried chicken, etc)
Solent nutritional meals
Foods That May Help Thicken Stool
Applesauce (peeled apples, no cores)
Bananas, Barley (when OK to have fiber)
Cheese (processed cheese food a clog problem, use real cheese)
Dried Chinese Crispy Noodles (severe thickening, mix with other food that causes diarrhea)
Marshmallows
Oatmeal (when OK to have fiber)
Pasta (sauces may increase symptoms) (in my experience more than a cup of pasta causes diarrhea)
Peanut butter, creamy only, nuts clog (may make skin greasy)
Potatoes, no skin (skin clogs, more than a cup may cause diarrhea)
Pretzels (salty may cause more flow water consumption)
Metamucil, mix or crackers (mix in a cup of water and drink before it gels up)
