Close Quarters

First off, thanks again for so many replies to my previous post. I confess I watch UFC matches from time to time because every so often you see some guy do something extraordinary in a circumstance where he's losing and suddenly he comes out on top. 99% of the time it's on the ground and the guy "losing" is remaining calm. I see people who are mounted get punched and turtle up while the guy on top beats on them until the ref stops it and tonight me and my roommate Beau wanted to test that. I've got a couple of pairs of grappling gloves and I let Beau get in the mount and told him to swing away and see if I could stop him. We later switched to where I had him in guard and same situation. Admittedly Beau is just learning about grappling but I could stop him from punching me without him landing a solid blow 8 out of 10 times from each position. The other 2 times he'd hit me once before I'd grab the arm or reverse the position or figure a way out of it. It's incredibly hard to punch someone when they buck you or throw their hands in that middle space between you and them while you're trying to hit them. Afterwards I wanted to work on my avoiding being punched while standing up. I tried Pat's Aiki brush-off several times and it worked most times. What I had problems with was that given we were in my garage on my mats, which are about 8' x 8', it's hard to stay out of ma ai. When contact is made, I noticed I could jump in and close the space, but that doesn't feel Aikido-like, but moving away doesn't do anything but free him up to swing again. I can't seem to get any solid off-balance while moving around in small spaces. Suggestions?