As usual, I agree with stinky. I never, ever cut anything from a flowering plant. The possible exceptions might be 1) if I failed to trim the lower scruffy crap off before going to flower, 2) mold or rot, 3) I just can't figure out a way to tie or bend a big leaf out of the way from shading a good bud.

And fimming is pinching or cutting off the top 80-90% of a new growth shoot, in hopes of sprouting about 6 more in its place.

Unless you have a nitrogen deficiency be sure to use only flowering food and supplements during flowering.