Approximately the same as in the flash version.
Simple way: You need to reach 4 hearts and "scold" the princess through dialogues until the maximum blue heart. Then the princess will not call the guards no matter what you have already done.
Difficult and "fast" way: reach 4 hearts, bring to orgasm, extremely quickly "click" dialogues about putting on a collar, and quickly start stroking her head before she calls the guards. In the worst case, sympathy quickly falls, when reaching 2 (or 3) hearts, the princess calls the guards and a plot with a bad ending begins.