my gf, now wife, would do that from time to time. the first time she did it I asked what she was doing, and she said she always wondered what it was like to have a penis "down there". she decided that if she was a boy, she wanted to have a "big one" like me. I even stood behind her a couple times at her request with my cock poking thru her crotch so she could look in the mirror. this was after we were married.
one morning she put on my underwear, stuffed a sock, rolled up 2 socks to simulate my cock & balls. shoved them into the underwear, then put on my jeans and walked around. of course none of this fit very well, we were laughing hilariously. she asked me how do I walk around with so much between my legs. I just told her it was my job to carry "her" cock around. we were in our 20's and fucked several times a day. she had a cock fetish, she blamed me, i gave her 1st orgasn, she had never had a big cock before, was amazed how it could go from small to "enormous" in a few seconds, was amazed i could cum and be hard again minutes later, was amazing how good good sex felt. life was very good and the sex was better.
