Daddy Dom Little Girl

Ok...So im not bring judgemental just trying to understand this lol. My cousins girlfriend likes to dress up as what she said is "Daddies little girl",she wears baby clothes,sucks on pacifiers and even wears and uses diapers. If shes good she is rewarded by her Daddy "boyfriend" if shes being bad he spanks her or puts her to bed early. As shes telling me this I couldnt help but laugh,it just seems so strange to me.She also said she medidtates for age regression until she feels like a 2yr old child. Apparently alot of people are into this? Does anyone else? Is this for sexual pleasure? Im so weirded put by this....