SUPPORT THE BAND: Purchase the official sheet music. My version was transcribed entirely by myself and is respectfully incomplete.
The liner notes for this album give a pretty entertaining lesson in the origin of this song's title. In very basic terms, it refers to a funky latin rhythm. If you want a better explanation, buy the album and read it yourself. The liner notes do not, however, state who is playing the trombone solo for this tune. I'm going to assume that it is Ben McIntosh since he is credited as the song's composer.
When I was in college, I chose this solo for a transcription assignment, and working on it again has brought back memories of sitting at the piano in a practice room, struggling. This time, I knocked out this whole transcription in just a few hours. So for you transcribers out there, it does get easier the more often and longer you work at it.
The reason I chose this solo for the assignment was that I could already sing it from memory. I had already internalized the melodies and it was a matter of figuring out the notes and rhythms on the paper. So, going back to the soulful and Kind of Blue playing from my last blog post, memorable solos are not always virtuosic solos, but rather, relatable solos. I can sing it, therefore, I can play it.
The solo is a great example of the fun of playing in a minor key. It's based around the G7 chord, the dominant chord, with a b9 (Ab). The interval between the b9 and the 3rd of the chord (B) is the natural tension of the C harmonic minor scale. Add to that some rhythmic syncopation, and now you're cooking! A perfect example is the arpeggio in bar 8 of the solo (up to the 11th, resolves to the 3rd, and back up to the tonic).
SPECIAL THANKS to Fabian Blättler for the comments!
Here's a YouTube video of some street performers in New Orleans playing "Summertime." The trombone solo begins around the 1:15 mark.
Recommended Reading: Travels With My Trombone: A Caribbean Journey by Henry Shukman. Published by Crown Publishers, Inc. (This may be out of print)