Means the word "sleep".
Orginiating from the word "Schalfen" In German but mainly used my teenagers in Scandinavia.
Became more and more used during the late 2010's.
Friend 1: Hey man I think imma go Slafen!
Friend 2: Okay man I think i'll go Slafen too.
When your'e about to do something involving "Burglary". But you want to evade cops listening.
Friend 1: Hey would you like to do some Burgle?
Friend 2: Hell yeah!