Advice on coming out to straight friends

Hey guys, so first time posting on Reddit. Sorry if this is too long.So I am 21 years old, with one foot out the closet (2 people know so far). I feel like I am ready to blast that closet door wide open, and start fully living my life. Actually I lie, I am no where near ready to tell my parents yet. But one step at a time I guess.I told my best friend last year, she was very accepting (as I knew she would be). It's been great to finally have someone I can truly be myself with, even if it is online, (she moved to a different city this year). Came out to my brother a few months ago, he was fine with it too. Although we haven't talked about it since.I feel like I am ready to come out to all my straight bros. I go to uni with them. Spend most of my day with these guys as we are all doing the same courses. I've known some of them for over 2/3 years, and few I've only met this year.Recently I find myself feeling guilty about lying by omission / hiding my true self from them. Especially when conversations come to girls.I am pretty certain they would be accepting. I live in a pretty socially progressive country (New Zealand), where being gay is usually not that big of an issue. I know one friend that might be a little... homo-ignorant?Only problem is I don't know how to go about doing this. I feel like it would just be awkward if I randomly/casually mention it. I was thinking of changing my wallpaper to the LGBT flag and go from there once someone notices it lol. I mean it would certainly bring up the topic.Any advice on how I should bring it up? What to say/not to say? Any advice in general would be helpful.TL;DR: Need advice on coming out to straight friends.