Mahlan conveys “gently,” “slowly,” or “have patience,” functioning as a softened appeal. Baʿḍa is accusative and qualifies the extent of hādhā al-tadallul, the beloved’s coy behavior.
Al-tadallul belongs to the root d-l-l and may express self-indulgent charm or the studied withholding of favor. Here the poet treats such conduct as emotionally burdensome.
Had the wording simply demanded “stop this behavior,” it would have been absolute. Baʿḍa asks first for some reduction, a nuance that makes the opening of the appeal more restrained.