Receiver, this Bearer solemnly swears to keep whatever indiscretion or potentially dangerous secret you have entrusted them with quiet for as long as necessary. It makes an excellent response to flowers such as It would be wrong, Danger and Alas – all of which place the Bearer in the graces of the Receiver.
Of course, should the Bearer subsequently break their promise – no matter what the situation, or the duress that they are placed under – then they will have to work hard to regain their standing, and for their word to carry any weight in future. Lips sealed can also be used to instruct the Receiver to keep silent - a sensible move, providing the Receiver is minded to do so. Bearers should beware of receiving It would be wrong, You've gotta be kidding me, WTF? or even Forgive me in reply.