edgewise

{ } adv. With the edge towards anything; in the direction of the edge. [ 1913 Webster ]

to get a word in edgewise to succeed in expressing an opinion in a conversation, in spite of constant speech from another or others; as, he talked incessantly and I couldn't get a word in edgewise. the form edgeways is now uncommon. [ PJC ]

Glad to get in a word, as they say, edgeways. Sir W. Scott. [ 1913 Webster ]