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 second base sexually?

--Second Base- Variously this meant tongue kissing, breast feeling, or outside the clothes genital contact. --Third Base- Usually this was a hand down the pants of you or your artner. --Home Run- This was ALWAYS sex, although it was rarely reached in the imes when you had to refer to it in terms of bases.