cumderwear

A woman's underwear that, after sex without a condom, begins to fill with semen that was not fully drained out when she went to the bathroom immediately following coitus.

Man: "That was some great sex."
Woman: "BRB, gotta empty out."
5 minutes later.....man and woman go out to get some coffee...
Woman: "It is still dripping! Now I have cumderwear! Ugh"
Man: <laughs>