I found this little gem while looking through old floppies. I had done a half dozen captioned images like this, but only this one seems to have survived the last decade. (The time-stamp on the file is November 2001.)
Being caught spying on a girls' slumber party is a common crossdressing theme. Usually the transgressing boys are dolled up in frilly lace lingerie, but honestly ... How many young, teen aged girls are going to have that kind of sexy lingerie?* Hence the more real world sleepwear these girl-clad boys are showcasing.
Anyhow, I hope you enjoy this artistic deviation (pun intended) from the BLSB style.
* I had an older sister and while we did grow up in a slightly religious home, she never had anything like corsets and garters or teddies and merry widows until she was around 17 and well past slumber parties. She did have frilly babydoll nighties which I put to good use on occasion, but 99% of her sleepwear and underclothes were more mundane.