Preoperatively, I counsel my patients that they should wear soft compression and cut a hole in it to pee. I recommend that they don't even try to sit at the toilet and that they pee into a cup standing up for the first few days. After that time, they can more comfortably sit on the toilet and resume their normal habits.
I allow my patients to go to the bathroom and sit down after thigh lift surgery. If pain is an issue and you are having trouble bending your hips to sit down, then you can urinate into a jar held against your skin to avoid any side splash. It sounds unpleasant but can be a really helpful fix while your wounds are tugging and sore.