1. In the US: cheating on one's usual partner. Recent usage, especially among teenagers.
2. In the US, anal or vaginal intercourse doggy-style (from the rear and on all fours).
3. In England, having sex in a parked car with people on the outside looking in. This practice is encouraged by some couples who turn on in interior light for the convenience of the viewing audience. Synonym: amomaxia (sex in parked car).
4. In England, watching people having sex in a parked car.
(Adult / Slang)
Sexual act/ritual involving the parking of cars in a desolate car park, interacting with strangers in other cars via a mixture of signals before committing sex acts with them.
Usage: I've been itching like crazy since that dogging session this weekend...