Alec ended up asking him the question directly to be sure, his body was literally on fire he couldn't wait for his man any longer: "My Liam what have you decided? If you don't say anything I'll take that for consent."
Liam took his neck and kissed him harshly, he was going to let Alec take the initiative tonight, he would let him do whatever he wanted, because it was his first time and he wanted him to remember it for ever.
Liam was also a dominant which was probably also why he had put off this moment as long as possible. Agreeing to be Alec's life partner meant he was going to have to make the biggest concession of his life, after all a red dragon would never let himself be dominated, even if Alec agreed, his dragon who was a deep part of him will not let him do it.
Liam and Alec also had bracelets to easily chanhe their outfits so with just a thought and a few seconds Liam was completely naked, offering his body to Alec.