It really depends on the intention; if you want to tell your product is sex heavy, then you can do that to warn others of what it is, if your product is story focused, you'd rather want to reserve such moments to late-game, where they'll hold strong emotional value, because that's how sex is generally viewed - a reward for staying for so long, or doing well enough.
I seen products that try to combine both, with varying success, but most of the time they were rather disappointing messes of both story and sex, which means people who looked for a good writing will be disappointed, while sex loving folk will be also pissed due to lack of actual sex focus they want. And that's the worst thing you can have out of 3 design option. And in fact, certain story focused games were ruined by sex scenes because their creators did them in a way they feel shoehorned, not natural otherwise and diminishing the value of the plot.
But in general, as long you have proper goal for a product, you shouldn't have a problem. Have a clear plan and don't try too much, or problems will arise with such direction.