Will anal masturbation damage my prostate?

Here are some... At 19, your prostate should be small and smooth so physical movement by whatever the tool used would not hurt the prostate, but does not guarantee to not injure any tissues in contact and irritation. So, exercise due respect to body and its tissue, especially anal canal is meant for poop not for sex - though having explored and exhausted by high intense pleasure-seeking fantasy. More? Ask doctor..