One can only sit on the fence so long without hurting
This quote springs off the English expression of “sitting on the fence” that means being indecisive, or waiting. While good things come to those who wait, another English expression, waiting too long will often also incur a cost with it. Not necessarily a cost as in with money, but a consequence. That’s the “hurting” reference here, that the cost will hurt you. But also, as a physical act, it would hurt soon enough if you ever sat on a fence! Most have pointy posts, or even barbed wire or just wire fences up to the top edge. None of them are actually very pleasant to sit on. I thought this sitting on the fence expression strange ever since I first heard it learning English decades ago. More recently, I’ve been able to put a metaphor to it for life actions to mean don’t wait (or hesitate) too long for things!