Using Masking Fluid with Watercolour

Masking fluid is a white liquid that you paint on and it rubberises.  After it dries out you can paint over the whole thing and the masking fluid area does not absorb the water.  When you wish to paint the masked area you rub it with your finger and it comes off.I don't often use masking fluid and there was a case where I could have used it on my Hollyhocks picture for the flowers but it wouldn't have worked. This is because when you cannot paint the flowers exactly as you would like them.  The masking fluid would have made them appear as a 'blob' and its shape would be all wrong.  When you try to paint around those its quite hard to do because you have a hard line around it. With the water lilies on my Scotney Castle Watercolour, they are flatter and it works better. There is a tutorial below taken from the Scotney Castle Watercolour tutorial where I use Masking Fluid.