A snap is also an insult, technically known as a 'dis.' In this respect, a snap is the singular form of The Dozens. This game, also known as Snapping the Dozens, is typically formed of two individuals snapping each other. In context: "Oh, snap...well, yo mama's so fat..." is the 'return fire' of a Dozens round; the speaker has acknowleged the point made by the previous insult and (in the same breath, lest he or she lose points for hesitation or having to think too long) gotten off a return. The phrase "Oh, snap!" could (at least in the 1970s and 1980s, dunno about now - izubachi informs me it is still in play, at least in the playgrounds of Midwestern America) also be heard on playgrounds as spectators reacted to a particularly impressive dis. In that sense, the user is emphasizing the severity of a dozens play (or other form of smackdown) by uttering the noun, emphasized; this is simliar to the weighted, satisfied use of the word "Touchdown!" at a football game, in quiet exultation.

For reference, as well as a knee-slappin' good time reminder of your playground days, read Snaps by James Percelay et al.(Quill Press, 1994). It's a collection of some of the best of them collected by topic - Mama, Sister, Sex, Fat, Ugly, etc.

An example opening round of the Dozens, with commentary:

"Man, you so stupid, you hadda ask for a price check at the 99-cent store!"

"Oh, snap...but you so stupid you gotta F in Romper room Coloring, yo."

[Ed.Note: Note the 'subject' has been chosen by the opener - Stupidity. This is a good, safe starter; it typically restricts insults to the recipient alone. At this point, in a 'expert' Dozens round, changing the 'subject' of the snaps carries meaning, and how it is done can display either strategy or desperation - and believe me, the crowd can tell.]

"Oh, snap...well, your family so stupid they think you smart!"

[Ed.: Tactical mistake! The snapper attempted the risky gambit of escalating to the 'family' level while not switching categories. This is double-or-nothing; it means accepting a restricted insult space (families) without broaching new subject matter (ugly, smelly, etc.) However, in this case, they were unable to complete a true snap in time, relying on the assumption of the opponent's stupidity. Since that's what's in contention at this point, it looks too much like 'declaring victory.']

"Ha, yeah, well they right, foo... [Ed.: Note the nullification of the previous shot, exploiting the tactical mistake; done swiftly enough to fit smoothly into the next insult, this is a coup. Relying on it to stand alone would be an indication of defeat!]...and anyway, you is so stupid you gotta read the directions on Minute Rice to see how long you gots to cook it."

[Ed.: A middling return shot. Done without hesitation, and coupled with the previous error, satisfactory, but short of true art. The other snapper, however, has used the extra second or two used during the acknowledgement of his or her initial error to think hard. Perhaps it was a tactical maneuver to buy those seconds?]

"Man, I'm amazed you can even read the box...[Ed.: Okay, it probably wasn't a strategy; the player is apparently using the obvious response to stall]...an' yo sister's so stupid, she got her first vibrator and cracked a tooth."

[Ed.: Play has been expanded. Sisters (explicit female relatives) are an escalation; bringing them into the game implies the insultee's inability to defend them, not just himself. One note, though: the Sex topic has been broached, but without actually performing a total subject switch. This is a good ploy, opening the Sex topic for play while not ceding the category to the other by an abrupt shift.]

"Oh, SNAP!....well finding yo' sister a Christmas card is easy, cuz so many addressed to 'Ho,ho,ho!'"

[Ed.: ...and so it goes, with an adept comeback which builds on the the previous shot's sister reference, upping the ante by folding sexual behavior into play. ]