Spotted things hidden by sailor beneath black undergarments (7)

'spotted things' is the definition.
The definition and answer can be both man-made objects as well as being plural nouns.
Maybe you can see a link between them that I don't see?

'hidden by sailor beneath black undergarments' is the wordplay.
'hidden by' is an insertion indicator (the outside letters hide the inside ones).
'sailor' becomes 'os' (ordinary seaman).
'beneath' says to put letters next to each other (in a down clue).
'black' becomes 'b' (abbreviation as in pencil hardness).
'undergarments' becomes 'dice' (I am not sure about this - if you are sure you should believe this answer much more).
'os' after 'b' is 'bos'.
'bos' enclosing 'dice' is 'BODICES'.

Can you help me to learn more?