The acting of rocking a mans member (aka sailboat) back and forth inside a womans vagina (aka cum-boat), this process is refered to as surfing her seas, after which the man finishes within her, this process is refered to as "unloading cargo"
*all aspects must be followed to be considered sailboating
Friend 1: "Dude, what'd you do last night?"
Friend 2: "Not much, just some sailboating."
Friend 1: "Idiot! Think she'll get pregnant?"
Friend 2: "I dont care, not my bitch."