Thanks :) I'm using Adobe Illustrator Draw. The iPad app allows me to export to Adobe Illustrator on Desktop. I then export the artboard in Illustrator to SVG and clean it up in Sketch.
http://www.adobe.com/products/draw.html http://sketchapp.com
Two apps that would work for you: Adobe Draw and Astropad.
Astropad does exactly what you want -- it lets you connect your iPad or iPhone to your computer over wi-fi, so that you can use it as a graphics tablet. It's a little bit clunky, but a lot of interesting UX tricks to make it feel more fluid, like previewing your lines while the lag is catching up.
My favorite, though, is Adobe Draw. With Draw, you can draw on your iPhone or iPad and sync to an Adobe Creative Cloud account. Then, you can open your drawings in a more robust desktop app (Photoshop or Illlustrator) when you're ready. Draw works in all vector, instead of being pixel-based, so you can then scale to any size with no loss in resolution. It's really great once you get the hang of it.