Saying

[Tammy J Holt]

Where does the saying 'tit in a trance' come from?

[Quizmonster]

It's possible that the word 'tit' in this instance is a variant of 'twit'...ie a silly or ineffectual person. The 'in a trance' just adds to that notion, with its idea of not being in control. Alternatively, it may just be another example of how we often use the name of a female body-part to criticise someone. I'm sure I do not need to illustrate the point further!
As regards who first said it, I think it unlikely that will ever be established.