Learn English – What to call light food served at cocktail parties, that can be eaten on the thumb

I think the word you are looking for is "humping", which is often used to describe simulated sexual activity in the way you describe. It can also be used to describe actual sexual intercourse depending on the context and usage.

It certainly is behaviour that is demeaning to a woman or a person who it is done to. There's an infamous video hoax that apppears to show former Italian Prime Minister Silvio Berlusconi doing this behind a woman on the street as he enters a building.

The other sense in which humping is used is when a dog decides to "hump" your leg. It may be trying to have intercourse with your leg, but you would probably want to say:

"Stop humping my leg"

And then gently shove him off your leg!

It is called a "hand towel" if used for drying the hands or face.

A similar but smaller towel is called a "wash cloth" (AmE) or a "flannel" (BrE) if used for washing the hands, face, or body.