when I worked in the newborn nursery and wanted to put a bow in the baby's hair I would make a little bow out of a thin piece of ribbon and then put a dab of KY jelly on the back. If you let it dry for a minute or two it would stay no problem and wash out with some water.
You can get that thin ribbon for like 99 cents a spool at most craft stores,.
They make some that have like velcro backs but I have yet to see anything that just sticks to hair. What I used to do is buy ribbon make a bow and stick it to Aspen's head using a drop of honey. Worked like magic! :)
My half sisters mom used to just tape the bows to my sisters head when she was a baby LOL
I don't know if they make any sticky ones or not.