Ihopeyourcakeisshit OK, I'll help.
Now, you have to imagine that mum has taken you out in the car so that we can discuss awkward things without having to make eye contact!
My understanding is that it involves someone, er, how can I put this. Ejaculating into another's anus and then, er, sucking the, er, matter out again and licking it all up? I can't believe I typed that. I'm off to burn my phone.