Green’s Dictionary of Slang

(US campus) unappealing or unpleasant.

1988		Eble Campus Sl. Oct. 10: velveeta – feeling one gets after talking to a cheesy person [...] I had to wipe the velveeta off me.
1996		Eble Sl. and Sociability 70: Cheese became a metaphor for ‘something unattractive or undesirable’ and gave rise to cheeseball, cheezy, velveeta, cheese whiz.