Slowly pass present back to grab attention (4,2)

'slowly pass' is the definition.
(as in time wearing on)

'present back to grab attention' is the wordplay.
'present' becomes 'now' (both can mean the current period).
'back' says the letters should be written backwards.
'to grab' indicates putting letters inside.
'attention' becomes 'ear' (having someone's ear is having their attention).
'now' backwards is 'won'.
'won' enclosing 'ear' is 'WEAR ON'.