What did Tom and Becky do during recess in The Adventures of Tom Sawyer?

During recess, Tom and Becky get engaged.

Tom had actually only just met Becky that morning during classes.  Becky had been interested in what Tom had been drawing, and Tom had offered to teach her how to draw if she would meet him during the lunch recess.  Becky agrees, and the two manage to get together back at the school without anyone else knowing.  Tom teaches Becky how to draw a house, and then "the two (fall) to talking", and share a piece of chewing gum.  The conversation switches to the subject of circuses, and Tom asks Becky if she has ever been engaged.

Tom explains that being engaged is when "you...just tell a boy you won't ever have anybody but him, ever ever ever, and then you kiss and that's all".  He whispers to Becky that he loves her, and goads her into saying it back.  Tom then tells Becky that all they need to do now to seal the deal is to kiss, and after a brief struggle, Becky submits.  Now that they are engaged, Tom tells Becky that she "ain't never to love anybody but (him), and...ain't never to marry anybody but (him), never never and forever...and always coming to school or when (they're) going home, (she's) to walk with (him), when there ain't anybody looking...because that's the way you do when you're engaged".

Tom and Becky's moment of bliss is short-lived, however, when Tom inadvertently reveals that he and Amy Lawrence had once been engaged.  Becky is aghast that she is not the first girl in Tom's life, and she begins to cry.  Unable to console her, Tom leaves, and when Becky realizes he is not going to return, she resigns herself "to hide her griefs and still her broken heart" (Chapter 7).