Perhaps the best position to give her pleasure with the tongue. If the man wants to make her beg for mercy, simple use the hands!
How to do it?
Step 1: The woman sits on her knees and leans forward to rests her head and hands.
Step 2: The man sits behind her on his knees and he also leans forward in a way so that he can kiss and lick her round and tight butt.
Step 3: The man holds both her thighs to apply strength with his tongue.