I was embarrassed. I could not keep the glider (a Blanik) anywhere
close to remaining calmly behind the tug.

Welcome to adverse yaw :-).

In 10 years of instructing, I've had exactly 2 power transition
students manage the tow with only verbal assist. It wasn't pretty, but
the job got done.

After a while, you'll realize that with a nose hook on aero tow, the
glider really wants to fly behind the tug and if it ain't doin' that,
it's you :-).

Tony V.