How can you not get hard when you are over your friend that is a girl's house who is really hot but you are only friends that hang out together?

It’s possible to feel attracted to someone without it leading to physical arousal, especially in a platonic friendship context. Emotional connection and comfort can sometimes override physical attraction. Additionally, being in a friend zone or having a strong platonic bond can help maintain boundaries that keep the situation from becoming awkward. Ultimately, each person's response to attraction varies based on their feelings and the dynamics of the relationship.