Is it normal for my sperm to dribble out rather than spurting when I ejaculate?

No. You may have a urethral stricture (narrowing). This should be suspected if it takes longer that normal to empty yourballer and the urinary stream is very narrow. If so, see a urologist.. You could also have partial obstruction of the ejaculatory ducts.
No. The peristaltic manner of sperm extrusion (ejaculation) is important in optimal deposition of semen/sperm in the vaginal cavity/as close to the cervix as possible, as it relates to infertility. Especially, if you're trying to conceive, get this checked out.