HELP!! First anal play, bootyho** feels...unstable?

I never had any interest in anal stimulation and I live a happy sex life. The thought did nothing for me and physically I’ve never felt any sort of “longing to be touched” or whatever. Today while masturbating I was moving around and my finger brushed ~the booty~. It felt nice and I continued, using the other hand to rub it gently as I went. I stayed on the outside, it wasn’t like it got railed with something huge but now it feels like poop and my whole insides could just dump right out of me. It feels so loose and not in a good way (is there a good way?) please tell me this is normal I’m afraid I need to wear a diaper something. when I stand up I think I could just start pouring 😩 nothing is actually coming out it’s just a horrible sensation please tell me when this will go away