touch base

native通信から。お久しぶり〜ね。

Yuji

Hello and how have you been? No doubt as busy as a ____.......fill in the blank:) I would have written "bee" but perhaps there is a more appropriate word.

Just touching base to see how you have been.

Take care and all the best.

Regards,

ここのtouch base はどのような意味なのでしょうか。luaさん，どうぞ。（UG）