What does the word 'spurt' in this Jethro Tull song mean?

English as a Second Language English Vocabulary, Grammar and Idioms
1

Hello Torsten/Alan:

I once went to a rock concert, the band was Jethro Tull visiting my country. I had the opportunity to ask the members of the band for their autographs and one of them wrote “Spurt” and then signed below.
What does this word exactly mean like a standalone expression ?

Thank you very much for this forum and all your help…!!!

2

I only know this word as both a noun and verb meaning rush forward or out.

3

Thank you very much Alan.