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When a person gives head( blow job ) and kisses someone, there is then a long white string attached from one persons lips, to the other. The white stringy substance is cum.
Guy: eww wtf, did you just give me a marshmallow kiss?!

Girl: umm, i guess. Since we're here i'm gonna go ahead and tell you, i've been cheating on you.
by V.r.d. 619 December 28, 2011
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