What the fuck kind of priest talks about sex at ever single Sunday Mass? Let alone, to specifically say it is evil and dirty (which would be him specifically preaching in opposition to what the Church itself says: I mean, I can quote you the Catechism of the Catholic Church, if you like, to prove that the Catholic position is almost identical to what SaturnOnWhatever is saying). I don't think I've ever heard a Catholic priest mention sex during mass, at all: that tends to be discussed in smaller groups that don't include small children, if at all. And, at least in my church, if he started saying what you said he said, which would be completely in opposition to the Church dogma, there are people in the parish who would confront him with his error.

So basically, either you're completely bullshitting, or your parents took you to some culty church that wasn't in communion with the Catholic Church. Was it SSPX? Or one of those bizarre American Churches that call themselves "Catholic Church of America" and suchlike, then basically do whatever they want?