telling/showing the right way is a turn-off

I don’t think OP is talking about a PowerPoint presentation (unless that’s your kink, you do you), but more like some verbal cues “faster” “don’t stop” “a little lower” etc. If the guy has a reasonable amount of attentiveness and experience, he should be able to get her 80% of the way there. Also, little cues like that can be hot as well because we know she’s into it and stuff.