I only can speak from my experience.....
First, it is more than just a hygine issue. I have to stop digits when the client has long nails.....
So, yes, washing ands before sticking that in is must, but some also need to be reminded to cut their nails short.
Second, finger fuck action you often see in porn movie, the two fingers going in and out in rough and speedy manner like a mad cow, the finger-fuck is not really pleasurable, at least to me. It hurts, hurts like a mad-cow.
Good digits that I truly enjoy is when you stick one finger in, find G-spot and gently pressure it while having my clit licked.
Mmmmmm, that's it... That's it...... Oh yeah...