It can't be determined whether this is futanari Wriggle or genderswap+trap Wriggle from the picture. However, it clearly is not a female Wriggle, since the spoken dialogue (and the lack of straps to indicate a strap-on) makes it obvious that Wriggle has a penis and is using it on Sanae.

Also, the 2girls tag and the yuri tag are mutually exclusive here.

Tagged by artist on pixiv as being male Wriggle.

I wonder if this is what Suwako stares at every twice in a month. :U