"I do not want to fierljep with you!"
Translation:Ik wil niet met jullie fierljeppen!
Fierljeppen is a sport, similar to pole vault, but instead of trying to get high as possible, it is about getting as far as possible, see this former world record.
In everyday use it is like below, but I think it's very rare, I've never seen it, but then I also don't live in Friesland. If it happens it's just the odd farmer when he's walking across his fields an then only certain farmers in one province (Friesland) if they actually are by foot and the sloten (ditches) don't have a dam or plank where they want to cross (so a lot of ifs):