affectionate play (or foreplay without contact with the genital organs)
If two people are petting, they are kissing and touching each other in a sexual way. Heavy petting: when two people kiss, hold and touch each other in a sexual way but do not have sexual intercourse.
Slang for foreplay, usually involving manual stimulation of the genitals.
Petting is the affectionate act of stroking, brushing or caressing an animal's fur, scratching its ears, rubbing its belly etc., for mutual enjoyment. Grooming behavior in some animals is similar to petting, but generally the verb "pet" refers to a human petting an animal—or another human.