What are the hooking up bases?

First base = kissing, including open-mouth (or French) kissing. Second base = petting above the waist, including touching, feeling, and fondling the chest, breasts, and nipples.

What is base 4 in a relationship?

Fourth base or home run. As the name suggests, the fourth base is about going all the way in your search for the big-O. It involves penetrative sex. If this is the first time for you or your partner, this is the point where you lose your virginity.