Kissing baby to sleep?

I'm just wondering if anyone else relates, my almost 4 month old baby boy is bottle fed and at night he drinks his bottle and then I rock him but if he's ever fussy and fighting sleep I just put my lips on his forehead and he passes out lol pretty much like a very pronglonged forehead kiss and if I move my lips when he's not in deep sleep then he'll stir or wake. Does anyone else do this??