Boston Kreme Filling or B.K.F Is a term used either in text or verbally when talking about the insemination or fertilization of a woman or in other words when you "bust a nut"
Boy 1:"So Cassandra and i just found out we're having a baby, and honestly i regret giving her a Boston Kreme Filling now."
Boy 2:"Well it's safe to say that now you're the one who's fucked."
Boy 2:"Well it's safe to say that now you're the one who's fucked."
by Penisrekt June 29, 2016
When having a menage-a-trois one person takes their fingers and shoves them in the person's ass and gets shit on them to wipe it on their partner's back and the other one cums in the mouth creating the Boston Kreme.
by AdolfObama November 29, 2019