What Causes Stool Leakage After A Bowel Movement?

I am taking an extremely long time to wipe my bum after defecating, usually it takes 30 wipes, and if I try to use toilet paper it takes an entire roll (not exaggerating, it actually takes a whole roll), so I gave up on that years ago. It's costing me a lot of money to continue buying so many wipes, and my anus is always sore afterwards from all the friction, my back is also sore from being twisted for so long. I'm wondering if there is something wrong with my wiping technique, or whether I have a health problem where my poos are too large and/or sticky, if such a problem exists? Right now I wipe until I no longer see anything on the wipes, is that too long, should I stop when there's still a bit of yellow? Also right now I am wiping the inside of my anus, should I be doing that or should I only wipe the outside? I apologize for the really awkward and embarrassing question but I can't put up with this problem for much longer and was too embarrassed to ask my GP.