Seepin' - Refers to a woman's vagina seeping menstrual fluids through a tampon that is ineffective. During this time which is known as a "period" a woman will tend to be bitchy, stubborn, and easily aggravated. Telling someone they are seepin' whether it be male or female is telling them that they are acting as if they were on their period.
Boy 1, "Hey Girl 1 stop seepin'!"
Girl 1, "What the hell does that even mean?"
Boy 1, "Aw gross! She's seepin all over the floor!"
Boy 2, "Yeah Girl 1 is such a bitch she's definetly seepin'"
Girl 1, "Hey Girl 2 am I seepin'?"
Girl 2, "Yeah kind of, you've been bitchy all day"
Boy 1, "Yo Boy 2, Girl 1 has been seepin' all day today hahaha"
Boy 2, "Yeah she's been a real cunt the whole day hahaha"