Jeff the Killer and Slenderman(or as he calls him, Slendy) have a very close bond. Slendy isn't the type to usually want direct contact with anyone, let alone to sleep with anyone, but Jeff is an exception.

Jeff is a charming phsycopath who has a lot of bloody hoodies, and Slendy kind of likes the smell of it, though he wouldn't even admit it.

Jeff's love language is more physical, while Slendy is more of a acts of service type. Jeff usually just clings to Slendy's waist casually.