Where can I find this video?

It is from Rin x Sen + Ran->Sem: Cross Mix.

Both episodes can be watched from here:
https://hentaimama.io/tvshows/rin-x-sen-ran-sem-cross-mix-haru-urara-uragiri-to-zetsubou-no-kisetsu-hen/





The GIF happens in Episode 2 at 26:35 mark
https://hentaimama.io/episodes/rin-x-sen-ran-sem-cross-mix-haru-urara-uragiri-to-zetsubou-no-kisetsu-hen-episode-2/

It is from Rin x Sen + Ran->Sem: Cross Mix.

Both episodes can be watched from here:
https://hentaimama.io/tvshows/rin-x-sen-ran-sem-cross-mix-haru-urara-uragiri-to-zetsubou-no-kisetsu-hen/





The GIF happens in Episode 2 at 26:35 mark
https://hentaimama.io/episodes/rin-x-sen-ran-sem-cross-mix-haru-urara-uragiri-to-zetsubou-no-kisetsu-hen-episode-2/

http://hentaigasm.com/rin-x-sen-ran-sem-cross-mix-2-raw/

Here you go! Literally the very last part of this episode

The series is called Rin x Sen + Ran -> Sem Cross Mix. This scene is from the end of episode 2. Not sure where to find it nowadays but I know that's the name of the series.