How to Not Feel awkward Around my Dads Friend?

Well Today I Peaked Into The Computer room To See If Anyone was On The Computer. Well Im 12 And Hes Like 47 && When I Looked In He Was Masturbating. He Covered up quick enough to act like he wasnt doing anything. He Looked Embarresed We Didnt Say Nothing But I Closed the Door Quickly He Might Think I Didnt see anything which i didnt see he Yhu Know What But I Saw Him Pully Away From His Yhu Know what nd His Pants Covered It. He has Lived Here for 4 years. He Supposed to be moving out soon Cause Hes Gettin mad money or w/e but Yeah. Hes Moving on the first. How can i not feel Awkward Until He Moves Out??