The foam party is a lot of fun. Honestly I think it's just another fun part of the whole trip, doesn't really stand out as above anything else.
There is a lot of soft swinging. A lot of doing body shots, licking chocolate off boobs, etc. etc. I think you probably see a lot more of that than actual swinging.
We were in our 30's and have been to both Pearle and RM. Had a ball at both. Depends on the crowd. Maybe in general the disco goes a bit later at RM but again it depends on the crowd.
The best activities through out the week is just hanging around the pool/hot tub/beach talking to people. Some of the random spontaneous fun that happens, that's where we have had the most fun.
You can find a lot of both full and soft swap....what ever you are comfortable with. Nobody will push you into something you are not comfortable with. I think you will find you will be pushing your own limits a bit. Again, you can find what ever you are into. A lot of the fun is the flirting, soft swap situations.
If you come to Desire.....don't plan on going to another resort....ever!!
Seriously, if you went to Desire then another Resort on the same trip I think you would be depressed. It's the one thing I definitely wouldn't reccomend.
Go, have fun and enjoy. Any other questions we'd be happy to help.