As some posters already stated:
If you fly the sailplane with your hand on the stick, there won't be any significant phugoid (I've flown about 3 dozend different gliders in 35 years, from 10m span to 29m span - never seen a phugoid while flying the glider).

If you take your hand off the stick, most sailplanes will start a phugoid.
Best way to end it: grab the stick and fly the glider.

Are you sure that you have actually flown a glider?

Bert
Ventus cM TW