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1.
A mcmac is the sexual action of filling a womans vagina with big mac secret sauce then eating it out, therefore bypassing the unbearable fishy taste associated with a vagina.
We went to Mcdonalds and ordered 5 big macs, scraped off all the secret sauce and i mcmaced her all night
by mcdsworkerr November 15, 2010
 
2.
The most delicious and fattening of all McDonald's products. It can only be ordered from their secret menu, to access this secret menu you must punch a cashier in the face while shouting McMAC!! repeatedly. If the cashier is still alive, he must then (company rules) proceed to give you a McMac.
Cashier: Sir may i take your order?
Customer: why yes could i have a MCMAC MCMAC MCMAC!
Cashier: OMG WHY WOULD YOU PUN...
Customer: *jumps over register and continues punching Cashier*
Cashier: ok ok, here's your mcmac
by Dextrine November 23, 2007