If i have gential herpes, can i pass it onto someone buy sucking there penis? herpes

No: If you have herpes on your genitalia only, performing oral sex on another individual should not transmit herpes simplex to their genitalia.

With oral herpes yes: By and large genital sex is not transmitted during oral sex. Safer sex is with a condom. There is some risk of transmision if u or partner inserts fingers into vagina and then inserts fingers into mouth or plays with partner's genitals..