If you're thinking of going down on someone in the back of a cab, should you:
a. ask the driver first and offer him 20 quid, thereby allowing him time to get his mobile phone and film you (not good)
b. just get down to it and rely on the recipient being able to get out their wallet and start throwing 50s at the startled driver, or
c. just hope the driver enjoys the ride too.
A fairly modern, and mucky dilemma. Answers on a £50 note please.