Lol Rsheikh. How about feed the mithai, dab oil THEN put mehndi :D Best thing is to let a sister or cousin sit throughout the rasms & guide every person who comes to feed the mithai. It works better that way.
You don't rub oil, just dab your fingers & kind of comb it through the hair. Its a Punjabi tradition if I am not wrong.
hibiscus to the list add uptan as well.