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The act of defecating on a woman's chest and rubbing the excrement onto her breasts. The female then proceeds to give the male a boob-job. A fully fecal phalice must be achieved for maximum rusty marshmallow...ness.
Yo I gave that girl a rusty marshmallow last night.

Ugh bro! I hope you washed your dick good at least.
by Oztheking102 May 02, 2017
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