The phrase "Once you ride a tiger, you can't get off" symbolically points out that once a person takes a risky decision or an irreversible step, they find themselves in a situation from which there is simply no easy exit.

Riding the Tiger: The Perils of Irreversible Choices

The phrase "Once you ride a tiger, you can't get off" symbolically points out that once a person takes a risky decision or an irreversible step, they find themselves in a situation from which there is simply no easy exit. In other words, having embarked on a dangerous venture, you end up caught by the force of circumstances that then dictates subsequent events, rendering retreat impossible.

This understanding is reflected in the following statement:
"Irrational forces have taken over Bolshevism from within. They wanted to ride a tiger, and now they cannot get off it. For a long time, Bolshevik power in the conquered countries has ceased to rely on enthusiasm; nowadays, it is maintained by the hypnotism of fear and the omnipotence of the Ministry of Internal Affairs. It might seem that this factor enhances the power of the Bolsheviks, but in fact, it is destroying it from within."
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Here, the image of "riding a tiger" is used to illustrate a situation in which the pursuit of experimentation or novelty leads to consequences that completely control the situation, leaving no possibility to reverse the decision. Thus, in the context of risks and irreversible steps, this phrase serves as a warning that diving into dangerous activities or making thoughtless decisions can trigger a chain of events from which retreat or a return to the previous state becomes impossible.