I absolutely would not use a bong (water pipe) as meth hcl highly soluble. Losing some to the water is obvious but drinking the water could easily end in a dangerous OD. I think smoking in an oil burner type pipe is the most sensible way to use for getting high. Obviously weighing out small doses and consuming orally should be safest but not as fun. At least with pipe you can slowly titrate your dose up to the desired level.
Decent meth is should be about pH 6-7 and almost neutral but it's very easy to over acidify and a lot of it is quite acidic pH 3-5 ish. Therefore I would not apply such an acidic chemical to the sensitive vaginal tissues.
If you do decide to then let us know how it goes. Feel free to take some pics for... eh... the sake of science

For some reason I'm remembering the time I cut up some ghost chillis and went for a piss... Not fun.