Well, she's supposed to open her mouth automatically when the dick's tip is pressed against her lips. If it's on her cheek, then you might be not aiming right. Though the controls really are, indeed, very awkward, specially since she's constantly trying to face the camera. You can change the direction she is facing by clicking and dragging her face, and how far and high her head is by clicking and dragging on her hair. You can also "aim" your dick by holding nothing with the right mouse button, though that also controls the camera direction. I should also mention that having too big of a dick kind of makes the whole sucking mechanic start to glitch.
Honestly, this game had potential, but it's still a mess. A shame the dev up and disappeared without a trace before he could make things more intuitive. People are trying to hack it in the discord, though, even though it's still going really slow.
