We have been in this situation before at times, mainly when my wife is off the pill and fertile we've opted for condoms, but I still get fed the used condom (which I love doing anyway, having our friend casually walking around the room with it full and dangling with him waiting for me to hurridly ask if I could ******* it down, hits the humiliation button for me big time, especially if you want it while its still warm... stone cold cum is a much more acquired taste) we have a regular gent so it less a worry of std's, but i'm sure its obviously still possible, but with no skin on skin contact it does lessen std risks... a little.