www444777com， i don't wanna be the third wheel.
third wheel 表示碍事的轮子， 多余的轮子， 引申为“电灯泡”
just go ahead with your boyfriend. i don't wanna be the third wheel.
what? you watched the movie with the lovers? you were being a third wheel.
什么？ 你跟一对情侣看的电影？ 你在当电灯泡呀。
i won't accept the invitation to spend the holiday with you two cause being a third wheel is so weird.