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2.
A man with a fairly ripped chest and arm package, yet has a full gut filled up for sex and other high intensity activities. Usually due to drinking huge quantities heavy beer such as melbourne/victoria bitter.
tom: gee your looking big in the gut.

john: its just my sex tank, got a threesome saturday night need heaps of fuel to get through it.
by the original dizzler October 18, 2010
 
1.
1) A sex tank is a complimentary expression for a female who has a physique characterized by a curvy buttocks, a medium waist and large breasts. However women like these are rare, perhaps 1 in 5,000 in the general population. 2) A solidly built-for-sex body. 3) A female that could stradle you and you would be very lucky. 4) A female body that was made to please a man.
"Damn. Did you see that sex tank in the store?"
by kaliandloki October 16, 2011