[TeNuaTe]

Sure your steering wheel locking isnt stopping at just the right place ?
Next time it does it be sure the steering wheel isnt held against the lock {the wheel should wiggle without hitting the lock}..if it is hitting the lock hold the wheel away from the stop then try the ignition again.

Rocking the car shouldnt affect the ignition lock hardly at all.....much less than actively pulling the key in and out etc.
Japanese locks are of the wafer variety rather than tumbler {although the term can be used for both}..anyway they tend to wear rather fast and become tolerant of the wear ..but none the less a worn key can become a problem.

An old trick is to intentionally accelerate the wear the wafer causes.
After you have the key cracked on just past the point of unlock....pull on the key with a couple pounds of force and start working{rotating} the lock to about 20 degrees then back to almost the point of lock position...rotate about 30 times...keep the pull on the key steady and constant.

Only do this once as it causes wear on the wafer where it contacts the key itself{from the pull}...our goal is to let the wafers cut a groove into the very soft metal ...thus allowing a sloppier key to operate the lock.

Dont pull hard... nor use tools or pull on the keyring.
A bare key being pinched hard with a thumb and finger is about right....as said keep the pull steady and constant as repeated pulls will cause wear on the wafer where key contact is made.