Second base, in the context of sexual or romantic intimacy, generally refers to touching or fondling above the waist, particularly the chest or breasts. This can include touching over or under clothing and may involve kissing or caressing in that area. It signifies a deeper level of physical intimacy beyond just kissing (first base) but stops short of genital contact or oral sex (third base)

. While definitions can vary slightly depending on cultural or personal interpretations, the most common understanding is:

• First base: Kissing, especially French kissing
• Second base: Touching or fondling above the waist, mainly the breasts or chest
• Third base: Touching below the waist or oral stimulation
• Home run (fourth base): Sexual intercourse

Second base represents a stage of growing trust and intimacy in a relationship, often involving skin-to-skin contact and more hands-on exploration of a partner’s body above the waist

. The metaphor is widely used in American culture to describe the progression of physical intimacy in dating.