This is a Jager-grenade, using 27cl plastic cup and 4.9cl plastic shot glass, place the redbull in the bottom cup the Jagermeister in the shot glass and when the pin is pulled the elastic band powered lever rises and allows the shot to fall into the cup, recommend using a split pin and a keyring ring for the pin. Definitely a work in progress I included the solidworks files feel free to improve and enjoy Printed at 0.2mm accuracy on a makerbot replicator