I probably saw this on TV in the late 80s/early 90s. I think it was a short film? Maybe part of a series? This idyllic looking playhouse is visited by a boy and a girl. Things appear inside, things they like, so they visit it more and more. Eventually they are absorbed into the walls. I remember their white faces trying to escape. Scared me! Lol.
Friday the 13th: The Series – “The Playhouse”
S02E12. you can watch it here: