Work that manhole, man, and you'll be an immeasurably better bottom for it. You won't be loose afterwards, and you won't be "stretched" - those are silly ideas thrown around by people who've never experienced truly huge playthings. Playing with your butt using bigger & bigger toys trains it to relax upon command. In addition, the more you work that muscle, the better you can control it to flex as well as relax. Google "kegels", or check out
https://www.sfaf.org/collections/be...urable-bottoming-from-a-physical-therapy-doc/
Best bet - learn your body without him around. That way you won't feel rushed or pressured, can back off as you need to, and pay attention to how your body reacts to different movements. Get some progressively larger toys and learn to relax with LOTS OF LUBE. With a little practice you'll be able to relax enough to take a pool noodle on demand, yet still tighten up enough to grip a toothpick. I'm not exaggerating with either of those.
Now man up and get that ass into the gym until you're ready to open up and milk that beercan like never before!