Hello. Thank you for writing to us at healthcaremagic Unprotected sex, no matter limited to a part of the entire sexual act, is a risk factor for transmission of STD. Having said that, longer the unprotected sexual contact lasts, greater the risk and vice versa. STD s can remain clinically silent for weeks or months and therefore I would suggest screening for STD s even though you and you boyfriend do not have any apparent signs and symptoms of an STD, as of now. Human papilloma virus/ Hpv has an average incubation period of 3 months (though range is few days to 20 months). Similarly, Molluscum contagiosum may also present weeks or months after it is acquired. Herpes can be clinically silent and many of those who carry the infection don t even know that they have it. Hiv too can be silent for months and year. Gonorrhea and chlamydia can remain asymptomatic, as well. I suggest screening for all STD s and moreover if you notice any urethral/ vaginal discharge, sores/ulcers, growths/warts on the genital area, you must get yourself checked with a venereologist. Regards