I've found the sites in the New Forest are generally more active than the ones in Bournemouth and Poole.
As a single guy you are likely to spend quite a lot of time waiting around in your car.
Patience is a virtue. It's best not to rush up to a couple as soon as they arrive. Most will give a signal if they want to play.
If you approach a couple who haven't signalled then you might be approaching a courting couple who aren't interested in dogging at all (embarrassing).
Signals include flashing brake, or headlights.
Hope this helps
Only a few lonely hours???
Agree its the not knowing what will happen that makes it. When you meet with a nice couple makes all the hanging around worthwhile.
For your first time dogging you might not want one of the more popular spots. These can get very busy and intimidating for a first time, especially on Friday Saturday nights.
Might be better to try one of the less popular sites, or go during the week.
Some couples will go to a popular spot and select some guys and go on somewhere quieter.
Anyway whatever you decide, hopw it all goes well and have fun.