Seriously guys you're much more likely to get something from receiving owo. Dental dams haven't caught on for a reason. You don't need them.
Just look, sniff and dive in.
1) why do people insist on saying X is more dangerous than Y when the danger is cumulative
. "You're more likely to get killed crossing the road than catch an STI from RO" might be true, but they are independent events, same with OWO and RO.
2) Dental dams haven't "caught on" because the demand for them is miniscule, not because they are "not needed". In what circumstance does someone need a dental dam? When they want to go down on a girl that they know or believe to have something unpleasant! Not exactly a high demand scenario, but if, for sake of a rarefied example, your wife had HIV but enjoyed receiving oral, would you not want to use one?