You may absolutely stay for both classes if you like! I will quite often go over the normal yoga poses in Beginner Class that I might have you doing in Partner Yoga with another naked guy!
Lately, I've been focusing on some arm strength and of course releasing our man stress from the hips. I've been going over modifications for planks, upward facing dogs and using ashtanga pranam instead of chaturanga during vinyasa flow. Come on in tonight and refine some of your practice!
And if you are in Partner Yoga tonight, make sure you say hello to your partner during your partner forward fold we fondly refer to as 'nuts to butts'.