Based on any one instance of the following, you may/can have been at risk for transmitting (giving to someone else) or contracting (getting it yourself) the following diseases and infections:
("blow job," "giving head," "going down," "rimming")
("hand job," or "fingering")
So, if you're sexually active and not practicing safer sex, or not sure if you are, check out how, and hop on it! And once you've started becoming in any way sexually active, it's time to start getting into your doctor or sexual healthcare clinic's office for those yearly tests.