1 definition by louhoo

When a couple is having sex with the girl on top unprotected and he cannot pull out being that he is on the bottom. She will proceed to jump or move as quickly as she can off of his penis and jack him off. Hopefully to prevent pregnancy.
I was about to cum, so i warned her, and she Jump n jack 'ed me off!
by louhoo December 26, 2009
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