That's called a " Prostate Massage". I know a few males who loves it. Don't know for sure though b/c I'm not a guy...so anyone out there willing to share some insights!!!
Seriously ...
Ummm...the whole hand in the rear is called fisting, and some men can handle it and some can't. Also, the prostate gland is like a g-spot on women, if it is stroked properly it can be very pleasurable. (I am not male, just know about anatomy)
... Ok ... （￣へ￣）
That's called fisting. Both men and women have anal pleasure spots, the whole hand isn't needed to locate them.
Strictly speaking a whole hand isn't needed in any body cavity ╥﹏╥
But mankind is all about "You won't know until you try" (that's why some people end up in the casualty department with a toilet brush stuck in their rectum... （/TДT)/ )
It's the first time that I had so much comment or reply to me in 4 days only and you guys give me many informations about it
Of course it's because I don't know anything about it even thought it's really rare to see that kind of situation that apear in Yaoi manga ... Because I read a lot of it so ( Yaoi manga ) ...
... I don't know if it was the last chapter so ... Anyway about the whole hand inside the butt when I saw it', I was like ... HOLY SHIT , DAMMIT or really ???!!! something like that so ... That's all !