d.h.c., n. — Green’s Dictionary of Slang

d.h.c. n.

[deep heavy conversation]

(US campus) a very intense conversation.

1982		Eble Campus Sl. Spring 3: dhc – deep heavy conversation.
1996		Eble Sl. and Sociability 36: Two kinds of shortening reduce words to letters. The dominant type in college slang is initialism, which names the individual letters: [...] DHC (deep heavy conversation).