St Petersburg Nudist / Visitor

Going to be in St Petersburg each week (not weekends) for the next couple of months.  Because I only have weekday evenings free, and usually not until a bit later in the evening (like after 7), nudist beaches and resorts aren't practical.  Being a hotel-room nudist is getting old.  Does anyone host occasional nudist house parties now and again and has room for one more?  Or maybe you've got other ideas?  Let me know.  Thanks.