Question: What is it? Is sex just for pleasure with your partner breaking a precept? Eg with a condom. And is being circumcised bad over personal preferences/ (hygiene,aesthetic)? is oral and anal sex bad? Is masturbation bad? And is circumcising your sons bad?

Answer: 
In general, the Pali Canon is quite exoteric and seems to equate sexual misconduct with various kinds of adulteries. Of course, for a monastic any sexual activity at all with the sole exception of involuntary nocturnal emissions is forbidden by the Vinaya.
Ideally, sexual pleasure should be avoided since it is craving. But Buddha knew that this was difficult for the laity. Therefore, he suggested that the laity should avoid sexual misconduct. Sexual misconduct is simply sexual behavior which is outside social acceptance. And you can interpret that according to your own society.