Ok opinions

How do you handle a friend who pursues guys you find attractive?

My dynamic with this straight man involves mutual flirting; he often offers to share drinks, and we exchange playful remarks. I mention how we might be together in another lifetime-corny, cheesy talk-and he responds with equal energy. Whenever we are near each other, we become nervous and giggly; we look into each other's eyes and laugh, or simply trade glances, which I attribute to our connection. Recently, my friend followed him on Twitter, formerly known as X, and now he says the man uses cute nicknames for him and what not? And to me when he came up to me like that, I was a little thrown off because I'm like he doesn't ever call me cute names. He has begun talking to him and liking all his photos. He is engaging with him, yet the man is straight. Why try to insert yourself when you do not know him that way and why do you suddenly need to all of a sudden start talking to him?? like it makes me upset because I had had this happen to me on different occasions, but with women and I just don't understand why!!! any help or input is highly valued.