The seal is Teflon coated for wear resistance, and there is nothing to put on it to help it seal. Richard is right when he said that the seal usually leaks because of solid waste on the sealing area, but the seals do eventually wear out, and have to be replaced (as a fulltimer I have to replace mine once every 5 to 7 years). However his repair method is intended for a manual flush toilet, and not an electric flush one like yours.
If there is a way to hold the flush ball open to clean the seal as Richard described, then that will probably work. If not you may be able to clean the seal by adding liquid dish washing detergent around the edge of the sealing area in an empty bowl. Then let it sit 10 or 15 minutes, and then add about a quart of water to the bowl and let that sit an additional 10 or 15 minutes before flushing. It may take several tries to adequately clean the seal.
If cleaning the seal does not correct the leak, you will have to replace the seal.
Gerald