It has been determined for some straight males, that twenty grand is the lowest amount of money acceptable for performing a blow job on another male. As an result, twenty grand simply became slang for asking for a blow job...and subsequently, if you give someone a thousand grand candy bar, you're asking for a long and sweaty night, 5 times over.
"Hey honey, you need twenty grand?" (guy) or "Hey boys, I'm low on cash, anyone have twenty grand I could borrow?" (girl)