A river of willows... so hilarious! What a great comic haiku, that one is. Try to think of a comic haiku about the river willow, if you can.
The River Willow
Flows upstream like a salmon
This is not funny
This is a jukugo word that uses the on'yomi readings of the kanji. And for once the kanji 川 doesn't use the kun'yomi reading. When you think of a comic haiku, think of something hilarious... like a centaur (せん), doing a standup act with a comedy haiku.
Could you write your senryu here?