Sexual consent matters.
Sexual activity without consent is sexual assault and is always a crime. It isn’t enough to assume someone has given consent for sexual activity. It is essential that each person in a sexual encounter is sure that anyone else involved has given their full consent. The best way to make sure of this is to ask them.
Many people with sexually transmitted infections (STIs) do not get symptoms, so it's worth getting tested even if you feel fine. If you think you have an STI, the earlier you're tested, the sooner treatment can be given if it's needed.