Green’s Dictionary of Slang

(US campus) to love, to hug, to comfort.

1988		Eble Campus Sl. Oct. 6: mommied up – loved, hugged, comforted: He was mommied-up by his girlfriend when he stepped off the plane.
1991		D. Jenkins You Gotta Play Hurt 276: ‘Boy, what a barf that fight was. Old Pork Chop mommied up to the canvas as soon as the bell rang’.
1996		Eble Sl. and Sociability 30: Athough English has dozens of particles available for word building, almost all of the examples in college slang use out, on, off and up: [...] mommy up ‘love, hug, comfort’.