Is it wrong how I feel about my son any advice

Ive caught my son jerking off multiple times when I acknowledge him he hides away but when I stand and spy on him jerking off he notices me watching but acts like he doesn't and continues to jerk off It turns me on most of the time I feel like offering help but feel awkward. I've walked in on him watching TV topless and nude sat with my vagina in his line of sight but nothing. Any advice