Perhaps, they are. Or your writing may be suffering from the ails of being too direct. Any scene that includes high intensity—this includes the erotic scene, as well as horror or war—walks a fine line. Looking at it too directly or literally can work against your good intentions to capture the moment.
Erotic scenes should be held to the same standards as any other scene. While they are the tart Granny Smiths of fiction, they are still apples. So, just as you don't lay a character's emotions bare:
Lindy wept out on the windswept mountain, her heart aching from the cruel wrench of betrayal; swelling from the weight of sadness.
So, do you not lay the eroticism bare:
Arnold caressed her fleshy rounded hips, cupping his hand around her firm buttocks and pulling her closer. Her skin was moist; her bosom heaving with expectation.
They both fail for being too direct—and relying on cliché—and easily hit the mark of melodrama.
You can remedy this by focusing your reader’s attention just to the side of the moment. The attention to a smaller, more nuanced detail can suggest a great deal. Karl Iagnemma’s "The Phrenologist's Dream," is the story of a Jeremiah, a phrenologist who travels the country by horse and buggy examining the shape of skulls. He falls for Sarah, one of the women he examined. This story achieves a high level of eroticism by looking to the side when Jeremiah and Sarah are alone in a hotel room:
She took the whiskey bottle and sipped, grimacing. “This isn’t a regular occurrence for me. I want you to understand that.” Then she slid the wig from her head and tossed it onto the bed.
A hot shock scalded Jeremiah. Sweat gleamed on the girl’s bare scalp, the skin silky and pale, as if it had never seen sun. She smoothed her palms over her head, then unknotted her dress and rolled her shoulders back, letting the clothes slide to her ankles. The girl glanced at him, her cheeks flushed with shame. Jeremiah lowered his eyes. His stomach trembled near sickness. He heard a hush of settling underclothes, then the mattress’ stiff rustle. She said, “All right, Mr. Simon. Now,” and touched his fingers.
He whispered, “Great God in heaven.”
While Sarah undresses entirely, Iagnemma doesn’t detail her nakedness. Rather, he directs us just to the side: unknotting her dress, rolling her shoulder’s back, her flushed cheeks, the sound of settling underclothes. These details describe what is around the moment of her nudity, evoking Jeremiah’s unease and excitement much more effectively than a direct description of her body might. Sarah taking off her wig to reveal her bald head is also an unveiling. She makes herself vulnerable, which adds to the intimacy of the moment.
Of course, you need not always look away when writing an erotic scene. Sometimes focusing the reader’s attention directly can create a spike in intensity. But too much can leave your reader feeling hit over the head, or giggling. Neither of which accomplish what you’re working toward.