Andraste's knickers, this thread updates at a ferocious rate!!

I'd simply like to state that pizza is awesome, and pineapple is totally acceptable on one. Especially when mixed with ham and mushrooms.

Thank you for the dialogue. I didn't say that the other banter necessary meant she must have had sexual experience with men (and if it was supposed to mean that, I hope the writer understands it couldn't be enjoyable for her no matter how well the man behaved in bed since she's supposed to be lesbian, so she couldn't give such advice based on her experience).
I just suspect it was written without much thinking about all those nuances. And your friends live in era when we're bombarded by sex-related stuff, particularly straight kind, with advices about bettering (straight) sex life in almost every women's magazine. Somehow I doubt that's the case in reality Sera lives in.
And that banter about Sera seducing a man for joke, up to the point of almost having sex with him, shows larger problem. On itself it just made me roll my eyes, but then I found out that Bioware writers made the only other confirmed lesbian character in this game, Empress Celene, do this for real, seduce a man and leave him naked and in bondage, leaving for player's imagination what happened before that point, despite unlimited possibilities she had to handle it different way, without humiliating herself like that.
And all of that after making Traynor in ME3 a fanservice for male player characters, a tease that 'innocently' kept displaying her charms in face of poor confused Shepard.
Judging from those depictions, one could guess that lesbians according to Bioware are apparently vixens up to seducing poor unsuspecting straight men just to play with them for their own enjoyment.
I saw a lot of this discussion when flicking around the various pages of this thread. There were loads I wanted to quote, but I can't find them, so this helps nicely. I've seen here (and heard elsewhere) a lot being made of the fact Sera seems to imply that she has/would theoretically go all the way with a man. There's a couple of different questions raised there.
I guess the main question I want to ask is: If Sera has ever been with a guy, does it matter...? As a gay woman who is of the "gold star" variety, I see an awful lot of hostility amongst lesbians towards women who aren't. I mean in general, not necessarily here. If a woman sleeps with men before she realises/can bring herself to accept that she only likes women, is she any less entitled to identify as a lesbian? IMHO no, not at all. And heaven forbid if a woman is actually bi...
Now I know Sera isn't intended to be bi, so that's a different point entirely. It's just a personal bugbear of mine how bi women are treated by gay women sometimes, but I'll spare you that rant. 
OTOH I completely understand the need for representation, and accurate representation at that. I never played as BroShep so I can't add too much to your comment about Traynor there, but as a female I've never had an issue with her portrayal. Celene is more problematic, I very much agree.
So is it the fact that Sera is Word of Godded as gay, and presents as such in game, so therefore anything ambiguous like this should have been left out of the writing? I find Blackwall about as interesting as drying paint half the time, so he never makes my party. Purely reading the dialogues, though, it's possible Sera is possibly taking it from the angle of how to please a woman and is actually taking a dig at the stereotype of male attitudes to straight sex...?