So if she was capable to seduce him to check why her friend love this witcher...she surely can even act drunk to take the situation and be closer again with him... just re-read the Blood of Elves chapter and see how desperately she wanted Geralt back...is she different in the game? I'm not sure.
Oh I know how desperate she was in BoE, and I think the way she feels about Geralt after she sees him again in Novigrad is very close to that. I also know that Triss is not above using shady seduction tactics, but in this case I though her actions weren't planned and came naturally. Triss' behavior toward Geralt in TW3 indicates she doesn't think it can work out between them now that Yen is back in the picture, so she tries to be as reserved as possible. She is not over Geralt at all imo, but based on the past experiences with him and knowing how he always goes back to Yen, she is just trying to spare herself further pain and humiliation.
When it comes to the party, I think Triss knew exactly what she was doing when she got him to chase her or the way she acted around the fountain. I see alcohol as one of the reasons(but only one of them, as I said in my previous post) for her opening up and allowing herself to try something with him, but I don't believe that her actions were planned though. If Triss wanted to seduce Geralt again, she would have acted differently prior to the party and not so reserved and trying to hide her feelings. And it doesn't make sense her master plan for getting Geralt back would be to pretend to be drunk and jump on him, it's not like Geralt has a drunk girl fetish or something. It just seems like a poor plan to me and honestly makes very little sense at this stage of their relationship. It would make more sense if she wanted to actually get drunk to gather courage to make a move on him and even that is unlikely, but pretending to be drunk...I just don't see it. I feel like the general mood of the evening spontaneously lead to Triss relaxing, dropping her guard and eventually making a move. I don't think she came to the party with a clear goal of seducing Geralt, but one thing led to another and it just happened.
When you are romancing Triss, from Geralt's perspective that quest is the one where you finally get to make a move on Triss. In their previous conversations Geralt can imply several times that he still has feelings for her, but Triss quickly brushes it off and changes the subject(warehouse scene, conversation with Dijkstra, complimenting her 22 inch waist, talk before the torture scene). Geralt is the one who initiates the kiss, so one can even say that Geralt was the real predator that evening and that he waited for Triss to get drunk and used the moment of her vulnerability to finally make his move even though she showed that she wants to move on with her life.
But, I'm not trying to find some ulterior motives in either of them. I love that quest, it's probably my favorite one with Triss, and I enjoy both hers and Geralt lines. I see it as a lovely evening for both, a breaking point and reawakening of their romance and I mostly see Triss' behavior that evening as charming.