1 definition by a japanese lady's plaything
In British English, "on a promise" simply means that you have arranged to or at least expect to have sex with someone in the near future - usually your regular partner.
Sorry, Dave. No drinks for me tonight. The wife found the handcuffs we used on our weddin' night, so it looks like I'm on a promise, know what I mean?
by a japanese lady's plaything May 6, 2007