I'm not sure if "sexually suggestive" actually fits this best or not, but from a quick run through Google translate, the image description has "('ll Leave to your imagination what is happening)".

Given the questionable nature of a translation like that and the image though, anyone feel free to correct if just sex seems more fitting.

I agree with you. He does say that, and the focus of the image and the rest of his text is her tits jiggling (purupuru in the image and description) - and it's called "Muginami-san's tits are the best in the world". Sex doesn't seem to be part of it, though is obviously suggested.