Based on personal experiences with both drugs I would not rec drinking heavily while on either of them especially xanax unless you particularly enjoy blackouts.
These substances should not be taken in the same day. Give your body a chance to purge itself of one before adding the other, unless you want to end up on dialysis, or have liver problems. Xanax And...
You should no eat/drink anything while the sub is dissolving. Once dissolved (about 5-10 minutes) you can safely drink. The taste is horrible, but if you drink- you are not getting the correct dosage...