What do we discover about the circumstances of Mayella's "rape" from Tom Robinson's testimony?
We discover that Tom did not rape her at all. Rather, Mayella lured Tom in to try to seduce him. As Tom is passing, she calls him over. Since Tom has helped her out in the past, he comes over, though he is wary. She asks him to help her an old door that is off its hinges. However, when Tom steps inside the Ewell's house, he sees that the door is in fine shape.
Then Tom realizes that it is quiet. All the Ewell children are gone. Mayella admits to Tom that it took her close to a year to save up 35 cents to send them to town. It is obvious here that she has done all of this to get Tom alone.
Anxious to get on his way, Tom makes polite small talk and gets ready to leave; however, Mayella makes one last request: she asks him to get a box down from atop a chiffarobe (the one Mayella claimed she asked Tom in to help her chop up for kindling). When Tom reaches up, Mayella hugs him around his waist.
Startled, Tom knocks over a chair and pushes Mayella away but not before she kisses him, stating that she has never kissed a man before and that what her father does to her doesn't count (implying sexual abuse).
When Tom refuses her, Mayella's attitude seems to change. She commands him to kiss her. Tom continues to refuse.
This is when Bob Ewell comes upon them and begins hollering. With no choice, Tom flees, a sure sign of guilt in a racist community like Maycomb.