Many do believe the rubbing the area around the opening is highly-stimulating, as is slapping or vibrating a hand over the whole kit and caboodle, and vigorously inserting fingers. Doesn't do it for me, and becomes quite irritating if anything.
Yeah, I've noticed a few of those ones, too.
I think also rubbishy "sex tipz" in Men's Health or whatever the blokes version of Cosmo is meant to be are slightly to blame; whenever I get a guy pushing down on the lower front bit of my tummy (I've read tipz that say this stimulates our g-spot?) when down there, I suspect the tipz may be the cause! I mean, I wouldn't honestly do anything that Cosmo told me to do with a penis, but then again, it's taken me about a hundred++ blowjobs to get good and we can't expect our clients to have gone down on that many women, especially not women who don't just ignore bad technique in favour of an easy life.
It's extra-complex, too, when you get to all those g-spot stimulation things - sure, I might enjoy a real lover having a good explore but often even then g-spot stimulation just makes me need to pee really bad. I'm not experienced or familiar enough at it to enjoy it with work at all (obviously I do not need clients "teaching" me sex stuff that I'm not already comfortable with; it just doesn't work and puts me off the whole thing) so while a client might have great fun following one escort's instructions on, I dunno, getting her to squirt or whatever, he can't just do that same prodding and poking to the next girl and expect the same result. I think this might really be a key factor in why we all have to do so much correcting!
I like to pre-empt things sometimes with a, "Just start
really gently and I'll tell you when to go harder/faster" (+flirty face) which can ideally save any of those awkward mid-prod/poke moments when you accidentally "meep" in pain and have to have that whole conversation full of the subtext, "I am not really turned on by your sexual technique" - always one best avoided!