As has been noted, if a dog is thrusting for more than about half a minute to a minute, he's either a rookie that can't find the hole, or he's a sexual oddball. Typically, a dog is a "once or twice a day" critter. Exceptions exist, but that's exactly what they are: exceptions. The vast majority are "one and done-for-the-day", assuming an actual full erection/tie/ejaculation. If they slip the tie with a bitch, they MAY come back for a second go-round, but unless they're sharing a domicile, the most likey behavior is gonna be "OK, it was good for me, hope it was good for you, seeya 'round - maybe".