もくもくrising (smoke, clouds, etc.), rolling up, billowing up

煙突(えんとつ)から煙(けむり)がもくもく立(た)ち上(のぼ)っている。

Smoke is billowing up from the chimney. {rising (smoke, clouds, etc.), rolling up, billowing up}

布団(ふとん)の中(なか)で子供(こども)がもくもくと動(うご)いています。

The child is stirring around in the futon, like smoke rising up. {rising (smoke, clouds, etc.), rolling up, billowing up}

黒(くろ)い雲(くも)がもくもく湧(わ)き上(あ)がり、雨(あめ)が降(ふ)り始(はじ)めた。

Black clouds billowed up and it began to rain. {rising (smoke, clouds, etc.), rolling up, billowing up}

煙突(えんとつ)がひっきりなしに煙(けむり)をもくもく吐(は)き出(だ)しています。

The chimney is incessantly billowing up smoke. {rising (smoke, clouds, etc.), rolling up, billowing up}

雲(くも)がもくもくと出(で)てきて、あっという間(ま)に大雨(おおあめ)が降(ふ)り出(だ)した。

Clouds started billowing up and in no time, it started pouring rain. {rising (smoke, clouds, etc.), rolling up, billowing up}