I think we have a terminology issue here.
A wing-down approach (or forward slip, being as you don't have the privilege
of being in the UK) is flown by rolling-out on the normal approach path, then using rudder to align the fuselage with the runway, then using bank to maintain the centre (center
) line - although naturally variations in rudder/aileron need to be coordinated.
Once the stude can slide all the way down final like this, teach them to transition to it from late in a crabbed approach (prevents the pax from having to be flopped against the sidewall for too long).
A typical difficulty is that people forget that they need to coordinate rudder/aileron once they've got them set-up.
HFD