It's easy. When you want to hunt rabbits, you go where there are rabbits.
Go to a nearby bookstore and find the "romance" section. Look for books with cover pictures involving guys with no shirt and women with their shirts nearly off. The common term is "bodice ripper." The titles should correspond to the cover art. Things about pirates and tropical islands and secret delights may feature highly. Buy three or four and read them.
Copy the methods.
Of course, the exact arrangement of words is copyrighted. But ideas and methods are not.
Just be aware of the verbed-his-adjective-noun construct. A safe example:
- He cast his smoldering glance at her glistening tax form.
This is troublesome but at first you may not know why it bugs you. Does he have more than one "glance" so he can save the others and only cast the smoldering one? Does she have more than one tax form such that he can afford to neglect all but the glistening one? It's lazy writing to combine things this way. Instead, try something like so.
- His glance smoldering, he ogled her tax form as it glistened in the moon light.
And one last bit of advice. When it comes to the sexy stuff, there is very little that will be enjoyed by absolutely everybody. No matter what you put on the page, some people will complain. So it's a question of taste and preferences. You have set out to do some "out there" content. So lay it on as thick as you can.