1. Age: When the male cat is young, the sex organs may not be fully developed, so Tintin may not be obvious.
2. Health problems: If the male cat is injured or infected, it may cause Tintin to swell or hide.
3. Before castration: If the male cat has been sterilized, Tintin may be cut off or hidden under the skin, so it will not be exposed.
4. Origin: Tintin may be different in size and color for different breeds of cats, and Tintin for some breeds of male cats may be small or difficult to detect.
5. Temperature and environmental factors: Male cats may shrink back in a cold environment, or hide Tintin in a comfortable environment to keep it clean.