You mean like GLENN FROM CHRONO TRIGGER???
It's a 2-parter.
First is setting up the angle and relative strength of the Tongue upon release. The release angle is just set to opposite of the PULL angle. Upon release, simply increase the radius of the tongue with respect to your origin point then when the tongue reaches its maximum length or when it hits an enemy, simply decrease the radius.
I can't build CAPX for you right now as I don't have time but
Look for Glenn's "Slurp Cut" Technique here:
at around time 3:54
to give you an idea. I'll make CAPX when I get time.