Not one for planning

So my partner and I are both very laid back people. We found out in August that we are expecting. So far he’s been at every appointment but I have one coming up in 3.5 weeks and he won’t be home because of work. (He works offshore, so he is home 2 weeks at a time). Anywaysssss, so I’m wanting to find out the gender and so does he, but he wants me to do a gender reveal for him. (Not a big party or anything, just something intimate for the both of us). Well I’m not sure what to do. Please ladies help a girl out!!!!