razor's edge, on the

To the point of doing something risky or dangerous. Please, you just like him because he's the bad boy who dances on the razor's edge with his motorcycle. I like to live on the razor's edge sometimes and go skydiving.

In a critical or dangerous predicament. This analogy dates from Homer’s time (Iliad, ca. 850 b.c.): “To all it stands on a razor’s edge, either woeful ruin or life for the Achaeans.” W. Somerset Maugham used it as the title of a philosophical novel (The Razor’s Edge, 1944) exploring the meaning of life. Alan White used it in The Long Silence (1976): “He was living on a razor’s edge. Sooner or later, the Germans were going to begin to suspect.”