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

[Ch01_Kelly]

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...!!!!

[Alan]

I only know this word as both a noun and verb meaning rush forward or out.
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English as a Second Language
You can read my ESL story Present Simple

[Ch01_Kelly]

Thank you very much Alan.