I headcanon that Astrotrain really likes sucking spike, no reason why, I just think he would. I think he would enjoy teasing Blitzwing while doing oral just to hear him whine and maybe even bark umm but that a headcanon for another time. I also think he's a throat goat, like he likes it deeep in him. Because as a shuttle and a train, he's tightly compressed, with more layers of metal then usual cybertronian he would be less sensitive, so imagine he would really like to feel someone really deep inside him for a change. While for Blitzwing is unusual to find someone that can fit his whole spike like that, so his tuff warrior persona slips off, when he's getting he's spark sucked out of his spike.