"Dis 'gina" (dĭs jahy-nuh) is a term of confidence used to punctuate a statement that is usually bold in character. A triangular arm motion with hands pointing towards one's own (potentially hypothetical) vagina is required each time "dis 'gina" is referenced.
"Dis 'gina" is akin to the terms "deez (d's or dese) nuts" or, "how about them apples?" It can also alternatively be used in place of a bud-ump-bump-chaa, 'Zing!' or 'oh snap!' at the end of a joke, or at random in conversation in place of "that's what she said" or "yo mama."
Kelly responded to Chris and Mike teasing her by making an apt and hilarious joke. She quickly punctuated her played response with, "dis 'gina!" *vagina hand motion included* to give the statement a 4realz degree of a authentication.