I ejaculate in my gf mouth,she spit out and deep kiss me,i spit out the saliva and then giv her oral. can she get pregnant from leftover sperm(might)?

Highly unlikely: Though it is highly unlikely for your partner to get pregnant from this practice it is worthwhile for you both to consider a better firm of birth control if you're trying to avoid pregnancy. Consider birth control pills, implants, IUDs, or injections to prevent her from getting pregnant. These methods are safe and much more effective than hoping something will work.