this 4koma was posted before in 4chan's /a/, and was translated by Anonymous:

[Since Summer Break's almost over...]
[Everyone came to the beach to play.]
"Huh? Where'd Sachiko go?"
"Eh? Now that you mention it..."
"She went somewhere with some guy just a while ago."
*pantpantgruntgruntetc*
"........ what are you doing?"
"Eh? Isn't the beach where you go to have car sex?"