Although vaginal intercourse in general is higher risk for HIV infection, cunnilingus is riskier for getting Herpes, HPV, Syphilis, Gonorrhea, and Chlamydia.
Whenever one gets tested for HIV it's always good to get screened for Syphilis too since that one often shows no symptoms and can cause serious damage to brain, liver, kidneys and various other things when left untreated.