Unless you do an arranged meet I suspect the chances of bumping into another couple are slim. Technically however that isn't proper dogging! As you've experienced dogging is luck of the drawer, partly why I've never cruised car parks. That and I keep reading about the boy racers ruining the fun. Sorry I have no top tips but Miss P does have top tits :-) Sadly she isn't around at the moment to come out to play though as fun outside is something we've talked about and are thinking about doing together too.