Certificate for a day at a spa (many are clothing optional). This is especially nice if you make it a day for the two of you.
Dance lessons for you and your partner so that you will wow your friends at the next dance at the club (if your partner would like this).
Membership, a packet of day passes or a weekend at their local nudist club . I’m sure most clubs would be happy to help you with this. https://www.aanr-nw.org