Can u get a std or a sti from fingering a guy in the anal area?
Yup - there are quite a few STDs which can be transmitted via unprotected manual sex of any kind. Safer sex practices like using latex gloves also make it much easier to prevent any bacteria from the anus getting anywhere else.
if you finger a guy in the anal area does the smae rules apply liek fer girls, using latex gloves and a water based lubricant liek KY Jelly?
Yup indeed. The anatomy of the anus and rectum is almost identical in men and women - the only relevant difference is that guys have a prostate gland.
And remember the other rules for anal play too - communicate, communicate, communicate, use way more lube than you think you need, relax, don't force anything, and stop immediately if anything hurts.
would that protect against diseases and how effective is that?
Using a latex glove and water-based lube is good safer sex practice, and should be very effective.