Need advice

So I am a guy in his late teens who is interested in one of his friends. Before I ask him out I want to be entirely sure he's gay. We're pretty close friends: we spend a lot of time together and share many interests, but I just don't want to accidentally ruin that. I know that there's no way to tell definitively from how he acts, but he's never demonstrated interest in women, has a moderately effeminate voice, has a case of "gay face," and some other physical cues point to him being gay. We used to have a lot of physical contact (like sharing a chair or putting an arm around the other), but he has rejected recent attempts for this sort of contact. I'm afraid he interpreted that differently (maybe as just being friendly) and would be uncomfortable if he found out I am gay and he didn't feel the same way. I've been trying to drop some hints, but I don't know if he is picking them up.What do I do guys? Should I just wait and just feel the situation out until I'm sure enough, or should I ask him?