In chapter 161, the ending tagline in the Gfantasy serialization reads "sekuharasuchan" セクハラスチャン. It's a combination of "sekuhara" セクハラ, meaning sexual harassment + "suchan" the latter half of Sebastian's name セバスチャン.

The format is reminiscent of adding "-bastian" to the end of words in English to make jokes/puns about Seb lol

It's kind of shame we don't get the Gfantasy manga serialization in English! Even the Japanese volumes don't include these little taglines (see below). So unless you get the Gfantasy release (or a scanlation of it), you miss out on these little jokes and comments at the beginning and ending of each chapter.

Thank you so much to @jadecircles for her explanation of the katakana!