To write sexy, potent, thong-dropping prose, deploy strong verbs.
At a moment of passion, the writer of limp prose declares, "Sexual pleasure is the most wonderful thing in life." It's true, but the phrasing is pathetic: The writer turns to the weakest of verbs, "is," to make this declaration. The writer has to pump up his prose at this point.
"To be" verbs just deflate a sentence. It would be ok to use "is" in a sentence to make a more tepid point. For instance, "Like masturbation, reading The New York Review of Books is a wonderful pleasure." But to use "is" in a sentence where you are describing the wonderful pleasures of sex conveys all the enthusiasm for sex that as a couple married for twenty years in an amiable relationship might summon up as they are about to make love on Saturday night from 11:20--11:35 pm.
The only way I would allow a writer to get by using "is" in such a sentence about sex is if the writer declared, "Sex is fucking great. Nothing beats it. Not even reading The New York Review of Books naked in a bath by candlelight."
A writer needs to insert some added emphasis--some vibration, if you will--into a sentence if he is going to use "is": For example, "I feel that sexual pleasure, heightened by eroticism or love, is the most wonderful thing in life."
Or the writer could be at once more romantic and more eloquent and more humorous if he or she wrote, "I feel that sexual pleasure surpasses all other wonders of life; yet too often we let opportunity for this joy pass us by, constrained as we are by a host of social conventions."
Here's another phrase that needs some verbal Viagra: "My desire is to have sex with you tonight." Instead, try "I want to make you sweat," or, more concise, "I want to fuck you," or, be more suggestive, "I want to make love to you all night long."
The best choice of words depends, very much, on the audience and the occasion, so that there are certainly times when "My desire is to make love to you" is the appropriate phrase, but other times, when the straight, bold, emphatic "Take me" (or "Fuck me") works best, and, yes, at times, you can and should be wordy, so that to get the point across repetition or verbosity is not a bad idea, as in, "Fuck me. Fuck me. Fuck me....yes, Yes. YES."