Comment by r0b1n

If you want to keep it very formal. Informally one would say something like "Trau dich, trinks!", or even shorter, "Komm, trinks!" or "Hopp, trinks!". Also depends on the exact intentions, if it were a bet, one could translate it as "Wetten dass dus nicht trinkst?", which would also state which side of the bet the speaker is on. "Herausfordern" is also more something like "challenge", as in "one knight challenging the other", less like "dare" as in "one child trying to get the other to do something".