It will be cool to see that in Nomad - This feature is avaliable in 3d coat and Quick shape for Blender by Jama.
The main Idea is you can choice some form (It can be Rectangle/ Oval/ Or maybe Custom Alpha brush) and just draw in 3d space or on 3d Surface!
Check this video to see how it works in 3Dcoat:
In Nomad Drag tool with high intensity does that.You can use stamps too.
It’s different as it creates a new geometry.
ZBrush has a thing as well ZBrush 2021.6 Mesh from Mask - Watch the Full Presentation in the Description - YouTube
Yes as variant but more like this Blender addon for Concept Art - QUICKCURVE! - YouTube
More Workflow
This quick curve is quite close to the curve we already have isn’t it?
There could be add one to tube like:
-Pressure to radius
-Autovoxel with objects named tube / with Sub and Add mode.
-create surface option for closed tube, instead of a tube it generates a extrusion of drawn shape, radius becomes extrusion height. Together with post subdivision it would be mesh balloon style.
Easy written down ideas, probably a nightmare to program. 