My bunny is a year-old Rex male and I have had him for about 7 months. He does this thing where he squats/crouches (like a dog taking a poop) and he pops/thrusts his butt repeatedly (about 3-4 times with about 3 seconds in between). there is a sound made that sounds like something hitting the floor/surface he is on. I think its his feet but im not sure. ive looked up “thumping” videos but the video rabbits arent in the position mine is in. If it helps any, he is not neutered.