The phrase seems to enthusiastically (gobaku) express a love or affection (moe) for a leisurely (tsurezure) or possibly carefree (free) experience with or as a mother (mama). Without more context, it's difficult to provide a detailed analysis.
Unlike Western "MILF" culture, which is often aggressive, the Japanese mama moe focuses on Think: A young neighbor who acts like a mother, a teacher who brings you snacks, or a single mother in a fantasy inn. The appeal is psychological safety, not just physical attraction. gobaku moe mama tsurezure free