I don't know, but you want to try it with me and we'll see what happens?
Well, it might make some sense ... the anal muscles are usually holding stuff in, and so contract naturally. When he is entering you, he is probably pushing pretty well, and overcomes those muscles. After he's come you're probably still bearing down on him pretty well, and once he softens, he can sllide out more easily. The head of the penis has the ridge that might be getting caught. The vagina, on the other hand, is designed to accept the penis, and so nothing usual happens when he pulls out.
Thanks - I like your reply better than the other one : )
Just an excuse to keep it in there. If you don't like it, don't let him in.