Middle finger, gentle but slightly firm pressure. Not a drill rig exploration. I don't think its so much about constant or intense pressure as much as timing it with your orgasm. It's a little hard to explain b/c it's mostly intuitive. I personally wouldn't use my own pinkie as it's not very strong (if that makes sense)... like a pinkie is just going to get lost
I had an ex-boyfriend who really liked it and guided me in "how-to" so some of it may just be you talking (gently) her through what feels good/what works/what doesn't.