It is best to use something non-petroleum based. Polysporin was what I was given. I was told by the nurses - do NOT use petroleum jelly or the like.
First wash with water and gentle soap. Then apply the ointment with a gauze pad, moving away from the penis head down the tube (to avoid pushing anything in).
Cleaning needs to be done several times a day, more if he has leakage around the outside of the tube (I did - had spasms).