Yes, it comes in a 1% solution. You should be able to get it at any drug store. It's used for cold sores inside the mouth, because it gets down into the tissue and won't wash off.
hmm, when I Googled it, the only things that came up was for use vaginally to treat yeast infections.
That's why I was curious if it had adverse health risks if you used it orally for a prank.
That's truly a sick one, I'm going to file that away for future use!