Hello. Thanks for writing to us at healthcaremagic As far as swallowing sperm is concerned, it is not an issue. Oral sex between partners is quite common and is considered normal sexual behavior. In terms of STD s, Oral sex has a lower risk in terms of STD s as compared to vaginal sex and anal sex. Having said that, unprotected oral sex is not entirely safe and almost all the STD s can be transmitted via this route if one of the partners is infected namely gonorrhea, chlamydia, herpes, syphilis etc However, if you and your partner have been involved sexually only with each other and never with anyone else in the past, it would be safe to assume that even unprotected oral sex is safe if it always has been between the two of you. Regards