What lmms-component are wi talking about?
Wave-shapes can be drawn in a couple of presets, and also a couple of lmms-effects. I think that the most difficult to draw is free-boy, because the area is tiny.
In general using mouse for drawing is difficult. I bought a tablet for ~ 15 $, and i have never regretted that 'investment'.
Event that simple and cheap tablet, gives you a huge advantage over any mouse.
You can most likely find a used tablet for sale online for ~ 10 $