As I don't have a vagina, I can only ask: is there a point of diminishing returns when it comes to using artificial lubricants for intercourse? Obviously, not enough is a bad, bad thing, but is it possible to reduce the friction enough to actually make it less pleasurable? Or is "friction" not really an issue anyway? I've read here and elsewhere that the vagina is mostly receptive of pressure and it's the filling/stretching sensation that's perceived more than any other. If that's the case, it stands to reason that the ease at which the penis slides in and out is irrelevant, so long as it's actually sliding. Forgive me if it's a goofy question, but I can say with certainty the slickness does affect the sensation from a guy's perspective, and there is a happy medium.