The act of a man having sex with a woman by repeatedly stroking his penis under her armpit. The term is similar to armpit sex, the armpit fuck, or dick in a headlock. However, it differentiates itself through the use of household items such as butter, margarine or cream as a lubricant to entice the woman to lick the penis as it protrudes from her armpit.
Man, I got a mean burn in my armpit from a Molly McButter last night.

I had to de-grease my penis after giving some Molly McButter to my old lady.
by Metairie Eric February 13, 2009
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20 Something girl who dresses like she is 80.
by Joe March 24, 2005
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A plain jane type female, often associated with the term 'white girl' -- though not always, generally at least loosely associated with a sorority.
I can't picture that Molly McButter getting down.

I'm not down for no Molly McButters.
by anonymous February 1, 2004
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