Marshmallow suprise 

When a guy's cum is so thick it has the viscosity of a marshmallow

Brianna: How was it last night?

Alex: I almost choked, he gave me a marshmallow suprise

Marshmallow suprise by Suprise Muthafucka February 5, 2014

Marshmallow Surprise 

A sex act where midway through intercourse the male defecates into a sock and shoves it into the females mouth.

guy: dude I gave my girlfriend a marshmallow surprise
guy2: nasty

Marshmallow Surprise by [Nex] February 22, 2009

Marshmallow Surprise 

Filling a pillow-case with cum and beating your friends face with it while they're asleep

Brad: Yo, dude. Jackson has been such a cunt lately...how do I fix it?
Johan: Give him a marshmallow surprise
Brad: What's that?
Johan: Grab a pillow-case and a camera, this is going to be epic

Marshmallow Surprise by frootyloopyinthebooty June 9, 2016

Marshmallow Surprise 

A seemingly delicious treat made from sprinkles inside mini marshallows inside larger marshmallows.

"Do we have marshmallows for the campout tonight?"

"No, Kara took them all so she could make Marshmallow Surprise."

Marshmallow Surprise by GS 882 October 18, 2008