Why do we need sex for long?
How long sex lasts make me wonder: Why does it last any time at all? All sex really needs to achieve, it seems, is to put sperm into the vagina. Why all the thrusting and bumping? Instead of sliding the penis in and out many hundreds of times per sexual session.
It is fun to go in and out! Does not care about fun per sex, it generally only “designs” things to be enjoyable if they helped our ancestors pass on their genes to future generations. For example, even though we like eating food, we do not chew each mouthful of it for five minutes just to make the enjoyment last longer. That would be inefficient and so we have evolved to find.