Press his lips together
He restrained himself and did not speak (literally: pressed his lips together).
(He said to him: "Ishmael, my brother: press your lips together and do not rush to answer" — Avodah Zarah 11a).
Translation
Expression (Hebrew)
חֵשֶׁק אֶת שְׂפָתָיו
Definition (Hebrew)
הִתְאַפֵּק וְלֹא דִּיבֵּר (מִילּוּלִית: הִצְמִיד אֶת שְׂפָתָיו זוֹ לְזוֹ).
(אָמַר לֵיהּ: יִשְׁמָעֵאל אָחִי: חֲשֹׁוק שְׂפָתֶיךָ זוֹ בָּזוֹ וְאַל תִּיבָּהֵל לְהָשִׁיב"- עֲבוֹדָה זָרָה לָהּ ע"א).