I am against frequent cleanings with anything other than water.
Too much of anything, even baby oil, will kill off any good bacteria that might be in there.
If the smegma is that gooey and sort of "drips" out, sticking to his hair, he possibly might have an yeast infection or some other internal infection that is causing all that excees.
While it's true that some geldings do have more smegma than others, there reaches a "beyond moderation" point that perhaps the vet should look at him.
Although, vets oftentimes just shrug it off as being "that's just who this horse is".
A lady on my local forum just went thru this with her gelding. The vet finally concluded he had a yeast infection and put him on some sort of antibiotics that did eventually clear him up. He also had a puffy sheath thru all of this.
I have a gelding that developed some serious digestive issues - I am pretty sure it was from his supplement fermenting, eventhough it's kept in the house and the bag expiry was 10-13.
Because he looked like a victim of "cow bloat" and had enough methane gas to blow up the barn, the vet put him on a prescription herbal blend.
It took two months but my horse's digestive tract did get cleaned out.
The smegma discharge has improved considerably but it's still not what I consider normal. I wipe him out as needed with nothing more than warm water and yes, he thanks me profusely.
Using anything but warm water in this type of situation isn't go to help. The next time the vet has to come out for someone, I will have the vet look at him again. But, for now, I keep all that winter hair around the opening shaved clear back to the skin so I can keep him clean -- with nothing more than warm water - yukky