“The creator of the Universe went to great trouble to create the foreskin. Then insisted that you cut it off. Makes sense.”-Richard Dawkins
Docking is something that can only be done between two people with cocks, and at least one or of them needs to be uncircumcised. Both guys get their cocks hard, and the uncircumcised guy puts a bit of lube on his cock. Then he puts it inside of the foreskin of the other guy and they have gentle sex that way. For most guys this is a really enjoyable act and even some straight men that experiment with bisexuality really enjoy it.
Some people prefer to use a bit of pre-cum instead of lube for docking, because too much liquid in there can actually make it not all that great. So it helps if one guy is a bit drippy, which is funny because that is something that is typically to be avoided. A lot of guys are afraid of trying this sex act because they don’t want to be seen as gay, but it seems to be something that a lot of dudes experiment with their buddies after a long night out or just because they can and it is fun!
Docking is a sex act that can result in fluid exchange so do whatever you need to do to have safer sex. It is often recommended that the guy who is uncircumcised wear a condom, but that does take away a lot of the sensation. The best way to figure out what to do is to discuss this with your sex partner and determine together what the best way to have a safe and fun docking experience is for you. That way you can do some docking without worry and just relax and have a great time.