Hey, I'm happy you're having fun the game! :)
The "you feel like something is preventing..." message indicates that you're missing a requirement. It could be that the girl isn't love level 4, or that they're already pregnant, or that you already have a kid with them currently in the day care.
Clothing options for "let's be naughty" scenes are added in as I find the time, but they'll all be added sooner or later! I update weekly, and it's just me developing CK, so I have to prioritize my time pretty strictly :)