As the girl opens her book, you move your chair a bit closer towards her. You poke her shoulder, but the girl doesn't respond at all. You poke the side of her B-cup breasts. The girl sighs quietly, seeming a bit tired of your antics, but doesn't respond otherwise.
You put one hand completely around her breast. The girl straightens her back a bit to make it easier for you to reach her bosom. You stand up and put both of your hands on her breasts now. No one in the class responds in any way. The girl mostly just tries to look at her book without getting in your way.
"Is this really alright?" you ask her. "I don't like it, but you're Allowed, of course. I'm not getting in your way." Her response sounds slightly annoyed, but otherwise neutral.
"Can you undo your top?" you ask, and the girl puts her hands in the air. "Do it yourself," she responds. You grab her sleeves and pull them up, eventually exposing her bra'd bosom. You drop her top on your own desk. You can't believe what you are doing. No one else is responding in any way. Hell, she is barely responding to you herself. The teacher comes in and, scared, you take a step back. As she looks over the teacher doesn't respond in any way, however. She opens her laptop and tries to open her PowerPoint presentation on the beamer instead.
You are unsure what to do next. You figure you'd ask the teacher if what you're doing is alright. "Uhm, miss Anderson..? Am I allowed to undo this girl's top?" You ask your question with a ton of doubt in your voice. Your teacher responds swiftly and without any emotion, however. "You can have sex with her for all I care. It would be nice if you'd stay quiet, though. Class is starting." The teacher faced the class. "Everyone else to their seats. And open on page 16."
The teacher went on to ask about homework. The entire class was paying attention as normal, but you are still standing next to the topless girl. "Psst, could you give me my top back," the girl asked, "it's chilly..."
"Miss Ericson, could you please be quiet during class?" The teacher didn't care at all about this girl's state of undress. You're wondering how you should further abuse this situation.