Similar to a booty call, but a more tactful euphemism in a committed relationship. When the maximum allowed time has passed without having sex, either by appointment or by arbitrary desires. Should be looked forward to in a healthy relationship.
1a. "You've been out there all day, it's time to get inside!"
1b. "Sorry guys, I gotta go- it's my curfew."
2. "I better be upstairs and naked by 10 tonight or I'll miss my curfew!"
John - ahhhhlright fellas im gonna scram, im getting tired
Doug - alright later curfew boy
John - dude i swear im tired
Doug - then fuckin leave curfew boy
And dying in yo' bed many years from now, would ya be willing ta trade all da days from dis here day ta dat fo' one chance, just one chance, ta come back here as young men an' tell our enemies dat dey may take our lives but dey will never take our freedom ... YUB NUB!