? Anode "Nut" Question -- Anti-Freeze 'Stuff"?

Don't have a 3/4" NPT tap.........don't what to buy one.......buy a short 3/4" pipe nipple. Use it to screw into drain hole to clean threads. Just screw it back & forth as you screw it in. (Cheap tap)

Then use the teflon paste or tape on anode rod threads.

Suburban water heaters use an anode rod.......either aluminum alloy or magnesium....as a sacrificial rod that dissolve due to galvanic action (electrochemical reaction) to protect the steel glass lined tank.