You can get the guy off faster if you have a tight butthole, and even more so if you clench it. My favorite technique is clenching on the way up and loosening on the way down and taking all of him. She just needs to learn how to accept his disco stick (push out like you're pooping; you need to relax your muscles and make your butthole bigger).
Of course, if the guy thinks he can just pull her pants down and stick it in, he's obviously never had a dick in his butt and is revealing an embarrassing lack of knowledge of how buttholes work.
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senorhousemouse