To blank someone's dong, is the act of ignoring someone's genitals when in clear view.
The phrase can also be used in the
first person, to 'blank your own dong' or 'blanking my dong'.
When used in this context, it means that someone is lacking
attention to there penis, and is most
probably not wanking.
Bro 1: Dude, totally gonna have a
threesome this
weekend!
Bro 2: Awesome! Just make sure you blank his dong!
Bro 1: Yeah, i had one before,
the other guy was just staring at it, he totally didn't blank my dong.