但し

ただし、調子に乗ると失敗を招くので注意！

However if you get carried away you'll risk failure so take care!

ただし、列をつくって並ばなくてはならないが・・・。

However, you have to queue...

ただし押し込む瞬間気圧の変化(へんか)のせいでしょうか、耳がツンとするのが難点です。

However, maybe from the sudden change in pressure when you push them in, having your ears pop is a problem.

ただし、学生(がくせい)の本分は学業ですから、期末テストをおろそかにしたらメッ！ですよ？

However, the duty of a student is to study. So if you neglect the end of term test, that's a "no!".

ただし、安全日だからって、中出ししても妊娠しないというわけではないらしいです。

However, it seems that just because it's a 'low risk day' doesn't mean that you won't get pregnant from intravaginal ejaculation.