Daryil loves his little games. In this instance, he's attempting to seduce Jakob by shapeshifting into him.
This is expanded from the last panel of page 19-07 from The Epsilon Project, which can be seen here: http://projectfuturecomic.com/epsilon.php?strip=19-07
Keen eyes may notice that the impostor has Jakob's eyes rather than Daryil's. I wasn't sure which to use, but went for Daryil keeping his own eye colour in the comic as an additional visual cue.
Chances are Jakob will be wearing the shiny whore gloves later anyway, once he's recovered from being kidnapped.
Either way, 'Go F--- Yourself' can be considered an offer among 'Cubi, rather than an insult.