expatiatingly

So as to expatiate; speaking or writing at length.

Japanese Meaning

長々と説明する、あるいは詳細に述べる様子 / 冗長に話す、または書く際の方法

She spoke expatiatingly about the history of the city, drawing the audience into every architectural detail.

彼女は街の歴史を詳述するために話し、建築のあらゆる細部を詳しく説明した。

Sense（1）

So as to expatiate; speaking or writing at length.