an abrupt and uncontrolled falling of a very large man
After almost falling out of bed, my husband proclaimed, "Wow! That was almost a manvalanche!"
by adc11 October 04, 2008
Half man, half avalanche.
Whoa! - Manvalanche, beware.
by Deadly Rob March 28, 2008
masturbation over the open mouth of one's sleeping romantic partner.
My woman fell asleep early last night, leaving me frustrated and triggering a manvalanche.
by maupin August 30, 2012