What is Merking?
1.
to drive quickly; to drive away from a sketchy situation
"shit, that car was merking down the road"
"the cops tried to stop him so he merked the fuck outta there"
See
2.
To creep around a bar hitting on women in a sketchy manner
I was merking on so many broads last night
See
3.
To, intentionally or unintentionally, appear in the background of someones photo. Someone who does this often may be referred to as a 'merker'
Look at you merking in the background of her photo!