Legend
L = light
H = heavy
J = jump
G = guard
xx = cancel
: = just frame
f = forward
b = back
u = up
d = down
Normals
L is safe against Vegeta, M.Vegeta, 16, Frieza, C. Frieza, Chi-Chi, Krillin, King Piccolo, and Buu. Each hit of LLH is bufferable. It has a just frame. Delaying the last hit will allow you to juggle afterwards.
H is safe if spaced properly. HH is unsafe on hit. Rolling is safe if spaced properly and may get you behind the opponent. H and HH can only be super canceled. HHH is bufferable, but there is a window where it can be interrupted.
Specials
Masenko has a long trail which can damage opponents. You can aim the beam with u or d while Gohan raises his hands. Once the head of the beam emerges, it's path is fixed and it will travel in a stright line. The L version does 2 hits and has faster startup. The H version does 4 hits and travels faster.
rpd+L gives you safe unparriable chip if spaced properly.
Spin Blade is an anti-air. Since it's a physical attack, you could possibly use it to cross up someone above you. DP+HH crosses up opponents in front of you, but it does very little damage and is unsafe if they block it correctly.
You can teleport through projectiles to punish them. It's fairly laggy. The H version travels further.