As you stated fingering is reserved manily for teenagers who want to "cop a feel". Punters should be using "stimulating the clitoris" to get a response which hopefully will lead to more or have an effect on the lady.
Some women enjoy a good g spot fingering but usually find this is not a Wg.
Fingering like DFK tends to be a boundary many Wg won't cross. To me if I can suck on her nipples and play with her clit I am usually half way there to submission.
BYVMD
4FoW2.