Rooney ended his second spell with the Club last week when he agreed a three-and-a-half-year deal with DC United.
“I was surprised when I got to know him better, he was so welcoming and his love for the Club was amazing," Tosun told evertonfc.com.
“He is one of the best footballers I have played with and has been one of the best players in the world, so it was a big honour for me to play with him.
“I will tell my children I played with Wayne Rooney.
“Always, when I am in Turkey or Germany, everybody asks me about Wayne Rooney. He is a legend all over the world."