What is Baba Ji ka thullu??

Girl and boy was Chatting on Facebook....
Girl - M very confused about 1 thing from last couple of days ...
BF - Tell me I will give you the answer! !
Girl - What is Baba Ji ka thullu??
Boy - ok ,when you Said me to Buy a Teddy bear for you last monday, what did you get ??
Girl - Nothing
Boy - This is called Baba Ji ka Thullu!