Humping / Dry humping

Humping - "Rubbing your crotch against something for stimulation, arousal and pleasure. Examples include humping your bed, the couch, the floor, pillow humping, and especially humping the body of another person.

Performed by lesbians when scissoring where the two partners interlock their spread legs (like two pairs of scissors) and grind their vulvae together to stimulate each other's clitoris to orgasm.", Urban Dictionary

"She was horny as fuck so humped the shit out of her pillow until she came."

Dry humping - "A physical act that generally takes place between two people and is basically non-penetrative sex 

At least one individual will manoeuvre their body into a position that would facilitate contact between the their genitals but participants remain clothed so, at minimum, their is underwear separating them (or alternatively sheets).

The people involved gradually rub against each other in an up and down or back and forth manner that mimics the act of sexual intercourse. This humping action allows for the participants to experience some degree of friction while engaging in this activity which gives a pleasurable feeling and can lead to orgasms for all involved.", Urban Dictionary.

"He forgot to bring a condom so I let him dry hump me instead."