"discreet" does not equal "discrete". They are different words with different meanings. That's all it means.

Moreover sex is most certainly not only between a male and a female.

And if the two having sex are adults it does not mean it is legal. Gang rape is rare. Rape by a single perpetrator is usual. It is not legal.

Having sex with a person one has control of because one wilds -- unjustly -- authority over and cna blackmail the person to exchange sex for a grade is in fact also ILLEGAL in virtually all countries of the world, whether you with your loose morals do or do not like that fact (though, granted, the law is not enforced everywhere with equal vigour).