how do you capture cum?

One of a number of practical things that comes along with bdsm play is to capture a man's cum to use in a number of ways. I've read about creating ice cum cubes among other things, but this is where the question comes up...

How do you actually practically capture the cum? And this without losing too much in the process.

And how about catching a woman's pussy juices for further use?

Interested in hearing you all's thoughts. :)

teach him or her to spit :-)

well with a guy grab a cup....with a women...well I'd say use a "spatula" type thing to scoop up?? lol..