I'm going to need major fan help here because I'm horrible about keeping track of ep names and stuff. Slowly I'm going to go off and research by myself, but if you have a John/Chi moment, send in the title of the episode and a brief description. You will be credited, naturally, and I will love you forever (which, granted, may be a less-than-compelling reason). If you have the date it originally aired, that would be awesome too, but it isn't required since... well, I wouldn't know either.

Kansas by Pipsthief
In Kansas, Chiana has to distract the young John Crichton so Noranti can get her knockout drug ready. Young John thinks her name is "Karen Shaw" and she distracts him by having sex with him. His first time, so as you can see Chiana was the one who actually took his virginity, he just doesn't remember it was her because Noranti gave him some dust, like she always does, to make him forget. So all he will remember is that it is some woman named Karen Shaw, not Chiana.