I offered OWO, but got freaked out. Basically I say that I still offer it, but at my discretion during the booking. I do the whole check thing disguised as a well lubed hand job, and basically always now just use my tounge on certain parts, eg. balls, just below the tip (obviously only if there are no dodgey marks or sores or anything), but when it comes to putting my whole mouth over, pre-cum etc, I put a condom on. Now I know there is still a risk, but I'd imagine that it is significantly lower as I do all my best to not really use my tongue down there for too long, and avoid all liquidly places...
I just try and give them a reallllly good hand job for ages so that they don't think too much about the fact I'm putting a condom on to suck them off... Since I've done it it's worked well, because I guess I'm not technically misleading them if I make it clear that it is at my discretion...