Letting sleeping dogs lie

When I was five years old, I lived in Sydney with my grandmother. She worked at an Op-Shop as the Manageress. There were many delivery men there over the years I remember her working there, but there was one in particular I will never forget.
His face is tattooed in my mind. He was balding and had a shaven head, but wasn’t old… maybe 40? His face is hard to describe, but it’s not important what he looked like really.
I was out in the shop playing with the toys that were for sale, as I usually did, I was five remember. I was sitting towards the back of the shop, next to the storeroom door. I heard what sounded like a man groaning in pain, I got up and walked into the storeroom. The deliveryman had his back to me but I could see he was playing with his groin area. “Are you alright?” I asked him in my quiet voice.
He jumped and began to roughly play with his pants, obviously surprised in being caught. “Yeah, you know when your shirt is tucked into your pants and it rubs against your belly and annoys you?” he ran through the words so fast I could hardly understand him. I just nodded my head in agreement. “Well yeah, they were like that and I had to fix them up” and he ran out of the storeroom. I never told anyone.
I’m not sure how much later it was, maybe a couple of weeks, I was playing with the toys and he was in the storeroom. This time I heard his quietly calling my name; I got up off of the floor and went out the back.
I walked over to him, I was nervous and didn’t know what he wanted. He pushed me towards the back of the storeroom where we couldn’t be seen. He undid his fly and pulled out his penis. My eyes just about popped out of my head, I had never seen one before.
“Touch it” he told me. I just looked up at him. “Touch it” he repeated. When I did nothing, he reached down and grabbed my small hand, wrapping my fingers around his dick. He guided my hand into a stroking motion “keep doing that” he told me and closed his eyes.
My whole body was shaking as I did as he told me. What hurts me so much now is that my grandmother was just out in the store. If I had screamed or called for her, she would have come in and stopped it all. I was too quiet and too scared to do anything.
He began to grow quickly in my hand. “Put it in your mouth” he whispered to me.
I looked up at him, tears pricking my eyes. When I didn’t do anything he grabbed onto my head, causing the tears to roll down my cheeks.
“I want my Nan,” I sobbed. The man looked at me, groaned, shoved himself back into his pants and walked out.
I sat down where I was and cried. Worse could have happened, but I was still so shaken up by the whole thing.
I never told my Nan about what happened, to be honest, I completely blocked it from my memory for years, until I was 19 and was talking to J. We were talking about child molestation and how the people that do it should be locked up forever. Suddenly it all came flooding back to me. I guess I just felt so at ease with J, that my mind relaxed enough for me to remember it.
He told me I should tell me Nan now, but I could never do that. Just let sleeping dogs lie.