exclamation of surprise, cry out (in anger), scold, talk, chat
咄 centers on sudden vocal outbursts: an exclamation of surprise, a cry of anger, or scolding. The talk and chat senses are less common extensions of this vocal expression.
咄 combines 口 (mouth) with 出 (come out), suggesting a sound or word bursting out of the mouth. The exact historical development is uncertain, but the component combination fits the meaning of an exclamation or scolding.
A mouth (口) with something coming out (出) captures the idea of a sudden shout or exclamation. Imagine a person whose words burst out like a surprise cry.
For トツ, imagine a sudden shout that sounds like 'tots!' bursting from the mouth: tots -> トツ, matching the exclamation meaning.