Hypothesizzle internal trigger doesn't allow a response by Taii Wakeen, Perfect Shot.

I cast Hypothesizzle intending to discard a card and then activate Taii Wakeen, Perfect Shot to increase the 4 damage to 6 and remove an opponent's creature. I had 4 lands untapped, but there was no opportunity to respond to the discard by activating my Taii Wakeen, Perfect Shot.