dogging in plymouth... where and what are the rules??

hi just intrested if anyone knows where in plymouth you can go dogging.. we went over to jennycliff the othernight. and it was full of boy racers.. so didnt stay long. but we were very intrested in going again. just to watch . lol but no idea on the rules or how it all works... didnt think it was a good idea to ask one of the men sitting in his car incase he was just walking the dog... for real.. or just watching the sun set.. so any info would be great.. x