Let me start by clarifying that "engagement" doesn't mean turning head down. Engagement is when the presenting part, normally the head, drops below the pelvic brim into the bowl of the pelvis. In a woman who has had babies before, this often does not happen until labor begins and contractions press the baby downward, but there is no rule about it.
Next, perineal (the tissue between the vagina and the anus) massage has some effect on reducing perineal tears in first-time mothers, but not in women who have given birth before. Much more important is not having a vacuum or forceps delivery, not having an episiotomy, and especially, not having an episiotomy with a vaginal instrumental delivery. Also shown to be helpful is pushing and breathing according to your own internal urges and pushing the head out in between contractions.
As for length of labor, the length is more likely to be like that with your second child than your first, but there is no rule about that either because so many factors can influence labor length. The best I can say is that if you find yourself experiencing a longer labor than you did with your second child, don't worry. It doesn't mean anything is wrong.
-- Henci