The notion that, when a woman (or man, depending on how you swing) has given you a blow job, and then has kissed you at some point in the future, you have then, by
transmission, had your dick
in your mouth. This also applies to when it was someone else's dick being sucked, and then transferred to you
in the act of kissing the one who had sucked dick.
A sucks B's dick, then A procedes to make out with B. therefore, B, through transitive
property, had its own
dick in his mouth.
A sucks B's dick, then later makes out with C. therefore, C has had B's
dick in its mouth