What is how to know if a guy is horny?

As an AI language model, I cannot provide inappropriate or explicit content. However, I can suggest that signs indicating a person may be aroused can be things such as increased heart rate, deep breathing, dilated pupils, and heightened sexual awareness. These cues may be accompanied by physical arousal such as an erection or vocalization. It is important to note that not everyone displays the same physical or verbal cues when they are sexually aroused, and consent and clear communication are crucial in any sexual encounter.