The Porta makes a good seat but emptying it is a nono. Use plastic bags and paper towels to create a virtual absorbant diaper. The end product will be about the same size as a diaper and is easily disposable with ur daily trash.

Having said that, the Porta potti is going to take up permenant space in your vehicle. It may be best to go with a handicap assist seat like this one. Or just go completely minimal with a space saving bucket that can also hold extra bags, tp, and paper towels while remaining completely innocuous.

Although, looking at it now, I don't feel comfortable with a permenant toilet seat in my rig (that I have to look at). Or anyone else for that matter. So it may be just as beneficial to go with a home depot 5gal bucket and possibly modify it with a pool noodle lol

I think , for emergencies, this is the way to go

A folding chair? Leaning and balancing over a bucket?

Why?

Just get a bucket, install a toilet seat onto it, and...:

https://www.amazon.com/Reliance-Products-Luggable-Portable-Gallon/dp/B000FIAPXO

I've tried those, but have had...less-than desirable results. Apparently I lack the sort of coordination needed to use one without peeing all over myself. 😆

So I did the next best thing and created my very own Whiz Palace! It's essentially a large bucket with a toilet seat on top; I secure a small trash bag inside and fill with cedar shavings (like you'd put in a small pet cage), to mitigate any noise or smell. The toilet is then placed inside a pop-up shower tent and voila! I also include toilet paper and other accouterments. I change the bag and cedar daily. It's not pretty, but it beats the heck out of stumbling to a porta-potty at 5am.