Dropping an adult on a child will have them attempt to read a story (to one child, or any in immediate vicinity) or teach (to all children on the island). If successful, the adult increases in parenting. I've done this with an elder (tells stories) and a master scientist (teaches).

Make sure to pick up a child first and drop them, so they're not doing anything. Then, pick up the adult and drop him/her on the kid. Can't remember if having the adult's primary skill choice set to parenting matters or not. Seems like you'd wanna change it to something else, as otherwise the game might think you're trying to initiate a romantic encounter with a child (ick!). But, as I said, I can't remember for sure.