Drew spot on hippie patterns (3-4)

I believe the answer is:

tie-dyes

I'm a little stuck... Click here to teach me more about this clue!

'hippie patterns' is the definition.
The definition suggests a verb in its -s form which matches the answer.

'drew spot' is the wordplay.
'drew' becomes 'tied' ('tie' can be a synonym of 'draw').
'spot' becomes 'yes' (I can't explain this - if you can you should believe this answer much more).
'tied'+'yes'='TIE-DYES'

'on' is the link.

Can you help me to learn more?

I've seen this clue in the Sydney Morning Herald.

Want a hint initially instead of a full solution? Install my app