Ladies of r/sex, how do I shave a girl's pubic hair?

Guy here. A couple of days ago I asked one of my girlfriends whether I could shave her pubic hair - she said yes. I've never done this before, so would appreciate a little help from sexxit.

I have already asked whether there is anything particular to her I should know (nothing) but I would prefer not to ask her for all the "general" information as it would dent the spontaneity a little.

Anyway, my questions are:

• How to start? Her hair is probably about 2 or 3 cm long at the moment, so can't attack with razor straight away. Beard trimmer to take most of it off first?
• What razor / creams / lotions? I have a Mach3, a bunch of fresh blades (!) and some menthol-based "cooling" shaving gel which I use for my face. Is this too rough?
• Position? She's probably going to be tied down (yeah, BDSM relationship) with her legs and arms stretched out. This may be too restrained especially for the lower bits, I don't know.
• Delicacy/accuracy? I don't want to cut her delicate parts- any tips?

Would also be vaguely curious if anyone else has done this and/or thinks it's hot.