Any article of clothing used to catch your blasted nut load. Examples are a sock, a shirt, maybe a towel or even your mom's living room drapes. A Gak Net used multiple times to catch your fapped out nut spunk may become quite stiff and crusty over time.
Darren found himself fapping to net porn in the living room. About to bust a nut, he needed a Gak Net. He grabbed the end of the designer window drapes and blew man juice and wiped up.