開大會的時候、腦子里想事兒的時候，我們很多人都會無意識地上下按動手里的伸縮筆筆帽按鈕，似乎那個“咔咔”的聲音能夠幫我們解悶兒或者讓我們更加專注。

Push pen anxiety is a psychological state characterized by one's excessive push-in push-out of his or her retractable pen, often due to stress or boredom. It is addicting because of its sound and its motion of going up and down. You kind of get hypnotized.
“按筆焦慮癥”描述的是一種心理狀態，就是在無聊或者壓力大的情況下不停地按動伸縮筆的筆帽按鈕。這種按動發出的聲音和上下伸縮的動作會有點讓人上癮，可能會讓你沉迷其中。

For example:

That kid at the back of the class has a serious case of push pen anxiety. He has been pushing his pen button for nearly half an hour.
班里坐最后一排的那個孩子有嚴重的按筆焦慮癥，他已經連續按動那個筆帽按鈕半個小時了。

（中國日報網英語點津 Helen）