The inside lining of the arse is highly absorbent : It's one of the easiest ways for anything to get directly into the bloodstream. And that includes HIV in infected cum and pre-cum / Terrence Higgins Trust, CHAPS.

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Credit: The inside lining of the arse is highly absorbent : It's one of the easiest ways for anything to get directly into the bloodstream. And that includes HIV in infected cum and pre-cum / Terrence Higgins Trust, CHAPS. Source: Wellcome Collection.