What is the liklihood of getting gonorrhea or another std from a single time receiving of cunnilngus?

No significant risk: STDs are difficult to transmit by cunnilingus; even the busiest STD clinics almost never see infected women in whom this has been the only possible exposure. The main exception is that if the oral partner has oral herpes (cold sores, fever blisters), genital herpes could result. But no measurable risk for gonorrhea or chlamydia.