That sounds hot!
Lock yourself in, put the cuffs on in front of you (behind if you are daring).
Put on a blindfold or just put something over your head and throw the key somewhere into your room (or outside again if you feel daring)
Now find it and don't sweat too much
Im going for the good old 'lock jeans' dare
I can lock it with padlocks, chains, or just without by squeesing the belt hold thingies together.