It's inflated at the present time in one of those blown up fortresses? (6,6)

I believe the answer is:

bouncy castle

I'm a little stuck... Click here to teach me more about this clue!

But I can't explain it at all! Could you help me understand?

(Other definitions for bouncy castle that I've seen before include "Inflatable structure for children's parties" , "[ENTERTAINMENT] loved by children" , "Blown-up, jumped-upon entertainment" , "Inflatable fort for children's play" , "Blown-up fortress?" .)

I've seen this clue in The Irish Times.

Want a hint initially instead of a full solution? Install my app