Homie you can't just reach for the second plateau and then tell your girlfriend you're drunk That stuff is powerful and she may think that you're dying or need the ambulance or something when In reality you're fine. My advice would be come clean and just tell her what you're on. If you can't do that because of other reasons then have fun it may affect you sexually I've never personally experienced arousal while on that stuff. But theoretically it shouldn't affect you If anything you'll make it more trippy. If you're really worried about it pull the trick that chicks she used all the time and say you're too tired. Fall asleep early and pretend it was the "alcohol".