A (generally) teen-age boy who spends the majority of his time masturbating into a tube sock. Sock fillers tend to be socially awkward, often standing slack-jawed while in the presence of their female classmates.
"As the girls' P.E. class ran past, a large number of sock fillers began to shift uncomfortably and mumble to each other."
by Jack Mahogov November 14, 2012
saggy ass titties that could completely fill a knee-high tube sock...it was originated in africa when poor black ladies were unable to purchase a real bra....they ended up using socks and powerade bottles
"dat grr wit dem saggy black tah-tahs gots sock fillers up in dat latino burrito"
by hairybungholeladygagajizzstain January 07, 2010