I'll complicate things even more - it depends on species too. With some carpets such as imbricata and spilota, where the male is usually smaller, combat is not common, you will often find several attending males together with one receptive female, all peacefully waiting their turn. In some subspecies, where the males grow large, mcdowelli for example,this is probably because they need the extra size and strength for combat, and typically two sexually mature snakes will fight.
These fights can be extremely violent, causing shocking injuries and not infrequently the death of one of the combatants. But the winner often mates furiously with his female afterwards. The best "low-risk" way of duplicating this stimulation in a cage is to throw in the fresh shed from another male whem you want some mating action - very effective.
Antaresias too are combatters as well, bhps as previously metioned.
Jamie.