I am currently on the quest for lucidity and the other night I was trying the WILD technique and when i was counting my breaths and using the tips, as my eyes were closed after a while doing the counting thing i seen fractions of fast flashing lights and they hit me and made a jolt. It happened about twice. Also when I woke 4 hours later it felt like I hadnt fallen asleep.
Is this common ?
Experiences like this, yes. They are the sensations of your boy going to sleep, that wasn’t a real jolt (unless you are in the habit of sleeping with metal objects near electrical sockets 
) but rather feelings of REM paralysis. The bad side is that they can be startling and take a little getting used to, you have to relax and press on when they happen, the upside however is that you are really quite close to success.
Try not to get to startled when stuff like that happens as it will bring you back toward waking.
Good Luck 
LM
Thanks
Good luck on you quest. 