This is harder than I thought it would be

I am a Registered Nurse with 32 years of Medical/Surgical experience.

If you don't milk your drain, it can get plugged up with mucus or blood and then where will that extra fluid go but into your abdomen to cause internal pressure, swelling and/or an abdominal abscess.  I would advise to continue milking the drain hose as instructed.  If the liquid coming out of the drain changes and becomes thick and milky, that usually indicates an infection that needs treatment right away.  Clear red/pink/orange/golden/yellow is acceptable, there may be blood clots or pieces of mucus or tissue in it which is also considered normal.

Also, excessive thirst/very dry, sticky mouth can be one of the symptoms of dehydration so be mindful.  It could also be a side effect of the anesthesia and pain medications.