Not a traditional lullaby and there is a swear word in it (that is easy to sub out!). However, it is a hit because:
1) it’s three verses that have repeating bits, so once memorized, it’s easy to recall again in the dead of night on very little sleep.
2) it’s in an easy vocal range and the melody is slow and very lulling.
3) fun, whimsical lyrics. I always changed the end from “you ought to give me wedding rings” to “you ought to give me sleeping” or “napping,” depending on the time of day.
4) the delight when your once-babies (mine are now 11 and 15) grow older and realize it’s a “real song” in the world, and marvel, “I thought this was just our special song!”
3 days ago