Help. Yoshimitsu's Flash!!

 Can someone help me how to practice the timing of Yoshi's flash (1+4) so i can juggle my opponent.
i've battled someone yesterday who is very good in using yoshi's flash i think 7 out of 10 of my blows is counter hit by his flash.
he's really good this made me more inspired to use Yoshi. can someone tell how does he do that.

...... im thinking that his reading my mind :o