It's rude to ignore someone after hooking up with them.
Kyle just had a fun date with Marissa, and they ended up sleeping together, so the next day Marissa sends him a text.
Kyle wants to read the text.
Kyle sees that Marissa was asking what he's up to later, so he texts back that he's free after he finishes cleaning.
Kyle sees that Marissa was asking what he's up to later, but decides to not respond because he was busy cleaning his house.
Marissa is thrilled that Kyle has some free time, so she can see him.
Marissa feels like Kyle got what he wanted from her and will probably not talk to her again which makes her sad.