You know when you wake up in the morning, and feel groggy. That's a jimmy. You know when you stumble to the kitchen, pour yourself a coffee, and it warms you inside. That's a jimmy. You get ready, head of out to work, and some passing woman smiles politely at you; it makes you happy. That sir, is the work of jimmy's. You get to work, decide you need a massive shit, so you go sit on the toilet, and slowly squeeze out a delicious warm smooth log, that pleasantly ripples as it glides through your anus. That feeling, that feeling there, is a jimmy.
Hope this helps.