STDs can be transferred from oral sex. Because many STDs have no visible symptoms, it's best not to assume that your friend is clean - and likewise, they'll want to be careful to protect themselves as well.
To make oral sex safe, use a condom. Not the top choice of many people, I realize, but flavoured condoms may make things more appetizing - as well as knowing that you are both protecting yourself from possible complications. [ alisonmarie's advice column | Ask alisonmarie A Question ]
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