Don's tackling tries in team practices (5,10)
I believe the answer is:
dress rehearsals
'practices' is the definition.
(dress rehearsal is a kind of practice)
'don's tackling tries in team' is the wordplay.
'don' becomes 'dress' (to don something is to dress in it).
'tackling' is an insertion indicator (to tackle is to take possession of).
'tries' becomes 'hears' (as in trying or hearing in a trial).
'in team' becomes 'reals' (I can't justify this - if you can you should give a lot more credence to this answer).
'hears' inserted within 'reals' is 'rehearsals'.
'dress'+'rehearsals'='DRESS REHEARSALS'
Can you help me to learn more?
(Another definition for dress rehearsals that I've seen is " full-scale practices".)