At first, it is painful, just like the first time you get fucked. But, the more you are worked, the better it feels. I am almost ready to take my first fist. My partner can get his hand in up to his thumb. We work on it nightly. I am wanting to go to a dungeon party and I want to be watched getting my ass worked over.
Getting pissed in is awesome! It is a great feeling. It is VERY intimate too. You trust your partner to the fullest and he trusts you!