Tugged one out over parents having it off in a bath of whipped cream.

My parents, both aged 68, were making orgasmic groaning sounds in the bathroom. I thought they had gone to brush their teeth or something, but I went to investigate - they're old and I wanted to check they were alright.

But I found them fucking each other in a bath of whipped cream. They saw me and I was aroused. I quickly undressed and started masturbating.

Now I feel all dirty and immoral. I'm sure I'm not the only one who has done this, right?

Is this normal?