Non-penetrative genital contact. Sexual contact that is not intercourse, oral-sex, or anal-sex or sexual contact where neither partner has a penis. Partners rub their penis, vulva, anus, clitoris, etc against each other. There is still a risk of STD/STI because there is still genital contact. There is also still a risk of pregnancy if ejaculation occurs.
My girlfriend and I have outercourse so that she can come too. I rub my penis against her clit before I penetrate her.
A sexual situation that involves either two guys and one girl or two girls and one guy. All participants have their clothes on and there is absolutely no penetration. Actions can include stroking, touching, rubbing, spooning, and manual masterbation. Common places to partake in this action are on couches or in movie theaters. CTWOs (as they are better known) are for people that aren't ready to go for intercourse or where it would be too akward to have interocurse with three people.