Just take it to the cleaners and tell them the stains are "protein", "albumin", or something like that. Say the cat puked on it, hell. Besides, what do you care if *strangers* even think it's all spunk?? They're not your Mom, they're strangers, after all!
I'd avoid washing the sheets or drying them, I'd even avoid getting them wet because that sometimes leaves marks on silk, depending on the dye. You can get the marks out if they're dry-cleaned, but until then, in my experience with shirts there's not much you can do til you take 'em to the cleaners.