When you are having anal sex(with a TS, male, or female) and the person on top, pulls his cock out of the ass and then rams it back inside and then pulls it back out. Usually, doing it fast or slow....this can create a massive sensation of pleasure, due to the nerves around the anus.
Damn, your cock felt sooo good when you were doubledipping my ass and slapping/rubbing the tip against my hole!
The appearance of cum around a the anus of a submissive man or female when taking cock raw. The pre-cum, lube/spit, or just cum build up inside the hole and all of the friction from going in and out of the asshole causes a self-defense mechanism from the sperm being exposed to oxygen and also being friction rubbed, which the sperm actually thinks it is being attacked and that is why the foam like appearance occurs.(this is true, the anus does NOT produce its own "wet/lube")
Omg, my asshole looked so gaped out and was straight up a creamed hole.