As Paul Skenes embarked on his MLB rookie season with the Pittsburgh Pirates, Livvy Dunne was by his side. The LSU power couple has become a staple around Pirates games this year as Skenes dominates his first season in the majors and started the All-Star Game last month. Saturday, Dunne turned the tables. She donned a Pirates uniform – with Skenes’ name and No. 30 on the back – along with a mustache during Fanatics Fest and tried her hand at throwing one of his trademark 100mph fastballs. After Dunne threw the pitch, she then broke into a tumble. That allowed her to throw in some gymnastics st…