hihi!! thank you so much!!
for sketching i use the sol brush which is quite popular (https://assets.clip-studio.com/en-us/detail?id=1778145). but basically any semi-opaque round-ish brush works. i like a LITTLE pressure sensitivity but not too much for sketching. but i also change how i sketch sometimes depending on my mood, im a chronic brush-swapper. but my coloured-sketches particularly use that brush for the soft lines tm. another thing i do for Soft Look is lighten my lines and turn them to multiply, and add EXTRA lightness to the skin /lighter parts of the drawing by airbrushing a white over those parts of the lines and turning it to an overlay layer (this does work with darker skin too, you just might have to lower the opacity a tad, it gives all skin a more soft look. which i personally enjoy in my porn art). what’s kinda “”important”” here is making sure its a multiply layer with the lighter parts, it gives my art this almost transparent line look?
for flat colouring i just use bog standard brushes, just anything that’ll apply the colours flat and opaque. i also use bucket tools
for shading i use a custom brush i made. basically the harder you press, the more soft the edges of the brush become, but it has a lot of pressure sensitivity so if you want more crisp shading you just press less hard. i also use a blur brush that responds to pressure sensitivity (any one will do) to kinda soften up some of my shading after too, like especially on thighs/arms/boobs etc. i don’t have my custom brush on the csp asset store, but i’ve seen many similar ones im sure you can tweak to ur preference <33 any sort of cel shading brush should work. you can also use any sort of mapping pen / gpen etc, and just blur the lines at the more soft parts of the drawing, that’s what i used to do