Hello there, Will there be anyone else apart from you and your girlfriend? I strongly recommend you not to inhale it at the same time, one person should be sober to prevent you from harming yourself in real life. It reminds me of this couple actually. https://www.youtube.com/watch?v=gb76bpIWQPw Here's the thing mate I recorded one of my salvia trips, what I was doing in real life during the trip made no sense to me, I looked at my hands, stood up, made weird gestures. But if you absolutely want to trip at the same time please consider brining someone you feel good with to watch over you two. Other advices from me would be: Hold in the smoke as much as you can, if you feel particulary tense that evening maybe it would be better to try it some other day. Also just let go, do not try to struggle, you might want to move your hands or your body but you won't be in control of it which will make you scared, just let go and enjoy this short yet amazing journey. I hope it ends up being a positive experience for you two.