Great Question Mr. Meatwhistle. I would say 2 on average mainly, because you are just in the act of finger manipulation as foreplay or to warm up your female companion. You don't wanna put in too many more than 2 because then it becomes about something more like Vaginal exploration(trying to determine the depth and width of her lady love hole).
A good rule to live by is the motto for the Shocker!
One in the stink and two in the pink.
I hope this post was helpful to you.
“Excellence is not a singular act, but a habit. You are what you repeatedly do.”
My freshman year of college there was this girl everyone called "Grand Canyon"... Needless to say once you got your hand near her vag, it attempted to swallow everything in it's path like the noble blue whale feeds on helpless plankton.