Wiktionary
play house
n. A child's toy domestic dwelling, either for dolls or large enough for the child to enter. vb. 1 To act out traditional housekeeping and family roles. 2 To live as if married without actually being legally married.
Wikipedia
Play House
"Play House" is a single by American pop music singer and songwriter Colette Carr. It was released on January 22, 2016 as the second single from her second studio album, Believe in Us. The music video was released February 3, 2016. Lyrically the song talks about fantasizing about role playing with a love interest, having the perfect life "playing house".