What you can do is go to training mode and put the comp on auto-block. Attack once (to make it block), then start trapping. If you’re doing it properly, the computer should not come out of blockstun at all. Any time the comp comes out of blockstun (and gets hit) is an opportunity for the opponent to jump out or call assist in a real match.
It’s possible to properly ‘trap’ your opponent without total lockdown, but you have to take into account your opponent jumping away or dealing with their assist. This, along with dealing with pushblocking, alpha counters, and juggled opponents are what dictate how well a Strider player can control his ouro. Along with some other stuff… ;p
Also iirc, after awhile the autoblock won’t block low attacks after awhile, so you’ll have to practice it without using lows… though they’re not necessary in the first place if you just want to practice your lockdown.