I think if vampires were real, it would be a known thing throughout the vampire community that a lot of humans have ticklish necks, and some vampires would have to give others tips on how to deal with that
"If your human has a ticklish neck, yes it's cute when they squeak and giggle, but they also scrunch their shoulders up which makes it hard to feed, so here's what you do-"
Also, in this world I think the humans are voluntary feeders and many of them form close bonds with the vampires and might be their primary feeder
And in this situation, I think sometimes the vampire gets playful and might hold them down just to nuzzle and kiss their neck while they pretend to feed just so they can watch their human go nuts
Gentle play bites or lightly dragging their fangs against the skin
And try as they might, the human is no match for vampire strength
Sometimes the human does it back to them and the vampire gets super fuckin flustered and giddy, not used to being on the receiving end
Also I think humans and vampires have a sort of symbiotic relationship here. The Vampire gets fed, and in return they will also buy or prepare normal food for their human to help them replenish their blood faster. If they bite a little too deep, they are the ones who clean and patch the wound
There's unspoken vampire rules that the community knows and they all boil down to, 'Dont be a dick and take care of your feeder human.'
Humans naturally bond with anything that moves, and vampires aren't an exception. So they might form romantic relationships, QPRs, or they might just be really close housemates
This was just supposed to be a tickle scenario, I didn't mean to world-build, it just kinda happened