Fingerstick lancets as sex toys
Of course, you have to be a vampire to properly appreciate it.
In the DUG series, vampirism is a disease, not some mystcial curse. It is contract by a person who carries a very rare gene when they are bitten by a vampire. Only these very rare few humans can be turned into a creature of the night. (Or a creature of delight in my stories!) And vampires crave the taste of blood during the sex act. It isn't necessary to complete the tango, but it adds an element of pleasure that can't be acheived any other way.
When the vampire Simon Molinar takes a human, Dr. Joe McKay, as his lover, he has to be careful. He can't bite his lover during their lovemaking because the doctor is one of those rare individual that carries the elusive vampire-making gene! Bummer for them!
Over time, Joe knows their lovemaking is missing something and wants to give that ultimate pleasure to Simon. So, being the resourceful medical professional that he is, Joe comes up with a device (usually used to help in testing a diabetic person's blood sugar) to prick his finger just before climax. He lets the blood pool in his hand and tempts Simon to lap the blood from his cupped palm. ( Anyone who has used a fingerstick lancet knows that the fingers are very vascular, and some bleed and bleed just from that one little prick.)
And wah-la! Fingerstick lancets as sex aids! Who would have thought it?