1.) Secret After work.

• "Aren't you strangely getting horny whenever you get tired?"
  Getting your coworker horny through tiredness from overtime work and drunkenness from alcohol♪

2.) Pushy Junior / Oshikake Kouhai (おしかけ後輩)

• At the home of her upperclassman who caught a cold, visits a junior who's more than a friend but less than a lover.
  She catches him staring hard at her boobs...

3.) Liar, You'll Do It Anyway! / Usotsuki Douse Suru Kuse ni! (嘘つき どうせスルくせに！)

• She's sick of the self-centered way her boyfriend has sex with her.
  He begs her for even just intercrural sex, but with his secret intentions his dick is even bigger than usual...

4.) Heijitsu no Hiruma kara (平日の昼間から)

• After finishing a shower, they're refreshed in the early afternoon.
  Skipping classes, lazing around, and when they kiss, the switch gets turned on♪

(Source: DMM)