[funinthesun]

I believe what Brandye meant with the rhythmic pressures was to do it at the same time the girl contracts. For the Kivin method you'd probably move to put pressure on the perineum after a couple minutes, gaging on your woman's arousal and reactions. There's really no set time, it's more a matter of reading your woman.

You'd probably want constant pressure, and increasing this pressure each time you feel a contraction.

This is just my personal experience from what girls preferred me to do, and what feels good when my own is going down on me while putting pressure on the same area.

As for when to start on the clit, here are some signs I've found:
Her hips begin bucking, trying to move you onto it
Hands have been randomly grasping the sheets/general writhing around for a couple minutes
Body quivers
vag/anus clenching and holding