Diaper, barrier cream question!? 1st time mom ;)

Sorry if naive about this & hubby says "I don't know" but I've been reading reviews about certain creams & ointments..Triple Paste for instance & moms are saying it works wonders as a barrier cream at night so baby doesn't wake up from wet diaper. We always put A+D after diaper change on our sons bottom but not too much in front/penis area but that's where he pees the most & only reason he wakes up at night! So, do moms put the cream/ointment directly on the penis or maybe diaper too? Totally clueless! Ha