Saw my niece and SIL in lingerie

So if anyone read my prior posts (if not no worries). I stayed my SIL place recently and my brother went out, not for long only 10/15mins, and they both said getting comfys on, pjs ect. Tipical movie night vibe as iv not been around as much as usual. However thought id go the bathroom as one does when every one else is occupied but past my SILs bedroom and her and my niece were looking and trying on lingerie together. Wow what a sight, didnt expect it at all!!

Part of me wanted dive right in there and then, but i also knew it wouldnt be long til my brother returned also.

Man what a night that was, soon as they went bed, straight beating i couldnt help it. Should i have done more?