78B originates from the Chinese pronunciation of the numbers 7 and 8. When pronounced together, 78b sounds similar to jiba b which means penis vagina in Mandarin. 78B is typically uttered when one feels complex emotions that are difficult to express.
I got bumbumed in that last test, fucking 78b.
78B! Sup bro, how's it going?
by ryanfagjiba January 14, 2015
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