Touch a bikini? (5)

I believe the answer is:

tanga

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

'bikini?' is the definition.
(a Tanga bikini is a kind of bikini)

'touch a' is the wordplay.
'touch' becomes 'tang' (I can't justify this - if you can you should believe this answer much more).
'tang'+'a'='TANGA'

Can you help me to learn more?

(Other definitions for tanga that I've seen before include "Briefs not covering hips" , "skimpy garment" , "underwear" , "Very brief pants" , "Skimpy briefs - a gnat (anag)" .)

I've seen this clue in The Guardian.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.