experts on STD's on medhelp pretty much say unprotected oral is virtually safe sex.
It is pretty much the opposite I think. Any form of sex without protection is risky....
You can check lots of articles about that on the internet. For example:
External Link/Members OnlyI was also several times in GUM clinics and they said the same thing. Do everything with protection. However its up to us to decide how far are we willing to go for extra pleasure which is OWO. I myself have never done bareback punt and will never do because its disgusting, but as for OWO most of the times I choose to go with it.
As for your original question, I personally know people who got STIs from OWO, hopefully nothing serious and they are all good now. Although is rare to get STIs from just OWO, unfortunately it happens
P.S. I think I saw a post recently about a punter saying he caught STIs from OWO and he is done with punting. Try to search it up