He had visited the three SEC schools numerous times prior to this last visit, but it was his first time in L.A.
It won't be his last.
"I was out at USC for three days and it was great," said Thompson. "I got out there Tuesday, then left last Thursday and I saw a lot of USC.
"Coach [Chris] Wilson showed me around and I liked the school a lot. I knew Coach Wilson from when he coached at Georgia, so it was cool to be around him again.
"At USC, I love the environment and I think I could play early there too. I now plan to take an official visit out there during the season."
The Trojans were not in Thompson's top group of schools before the visit last week, but USC is up there high now.
"USC moved up to No. 2 for me. They moved ahead of Auburn and Alabama. I just liked it a lot out there and I want to get back out there again. The whole visit stood out to me."
The Trojans still have plenty of time to climb to the very top of Thompson's list. At the earliest, he will commit after the 2014 season. It could even be signing day.
It could be tough for USC or anyone to knock the in-state Georgia Bulldogs off the top though.
"Georgia is still my No. 1 school," said Thompson. "It is just different for me there."
"Georgia is the hometown school, I love the coaches, and it is home for me."I will watch the season, see how the different teams do, see how coaches do, and all that, but Georgia is a strong No. 1 for me."
The No. 1 defensive tackle in the country on Scout is not alone going through the recruiting process. His mother is right there with him too.
Thompson knows she will have a say too.
"My mom is important and she takes visits with me, she speaks with coaches, and she looks at the schools too. She has visited Georgia, Auburn, and Florida State so far and I she is going to Alabama with me in July.
"She is helping me with all of this. It will be my decision, but she is helping me with it."