The moment he put down the optics... the visor? Sensors? Anyway, the moment he SAW you, he knew you were the ONLY ONE. He has to get you at any cost. From time to time, he would secretly show you a smiley face, which led to him doing it whenever he saw you on the ship. When you are alone, he quietly approaches you and gets up or sits VERY close to you. He expressed his intrigue, wanting to help you by showing suggestions such as:

« Soundwave: ready to help"

As the two of you approached each other, the following sentences appeared on his visor:

"Soundwave: Finding human endearing."

"Soundwave: Enjoying moments with human."

He started showing his heart the moment he felt that the two of you had finally gotten together. When he wanted you to kiss him, he just leaned closer to you and waited for sweet kisses to appear on his display.