The affection was caused by the immature larva, and has mostly subsided, though such obvious displays are a threat to our anonymity...
((What do the larva look like? could they be mistaken for a worm, maggot, millipede, or any other familiar terrestrial entity?))
The native forms of intimacy can have significant social repercussions, we should attempt to remain aloof until we have a long-term plan for our social position during the infiltration.
We have yet to identify the native undead, and the acquirement process would likely overwrite their undead natures, if they even possess sufficiently stable vitality to host the impregnation.
It does seem that we need to use either stealth or surprise to infest others, the question I want to know is this: do infested humans gain a exoskeleton (or whatever) like we do? If we're going to try to infest someone via having an infested human date them that could be a problem...
Mosquito larva are slightly smaller than a ping-pong ball and look like large white gray maggots. You have yet to make any other kind of Larva, so you do not know what they look like. You doubt larva variety carries much in size. Larva are fairly intelligent and can do some basic problem solving to reach and infest a marked human, however unless the pheromone is applied only to an orifice the Larva will attempt to chew through the skin, leaving a tell-tale entrance wound.
Once inside the host the larva nest inside the skull, eating and replacing the human brain. As it grows it spawns long tentacle like growth that extend throughout the body consuming and replacing whatever nervous tissue it can find. The growths also are used to rapidly consume the host body from the inside out during the hatching process. Nobody will be able to detect an infested human unless they attempt surgery or run them through a MRI scanner.
Larva will only cling to the skin of you, a moth, or a spider. You could cover an infested human in reward pheromone to attract larva, but it would also put the human on a reward pheromone high, making them useless for most tasks.