She can most likely tell, so long as you make some kind of sound that is different from the noises that you normally make during sex. Besides, why would you need to tell her for intercourse? That being said, I assume that you are using a condom. If you "pulling out", then hell yea, you need to tell her.

I am on the pill, my b/f usually tells me and then either cums inside.... or pulls out and cums on my stomach/boobs.

I agree with cjb, and then there is this: it all depends on what you want for a conclusion. Many a woman wants to do more to help the climax along sometimes by perhaps squeezing a testicle, massaging the prostate (more vigorously), or grinding or humping more energetically. So, yes, while it is not absolutely necessary to pass along a status report, I believe you can see the benefits and rewards when you sometimes do.

When I'm receiving oral sex, my girl likes me to tap her on the head right before I cum. That way she knows, and she's not surprised, or whatever. She swallows, but still, she likes to know.

So, generally, it's not a bad idea, I'd say.

well you can usually tell but until she can work it out for herself then i say tell her. there is no harm in letting her know

[QUOTE=tmps;176724]well you can usually tell but until she can work it out for herself then i say tell her. there is no harm in letting her know[/QUOTE]

Agreed good advice

It's polite to let her know. My boyfriend always tells me because I got pregnant once before but miscarried and I'm scared to death of it happening again, so I won't let him cum inside of me. She might have the same fears and her freaking out or getting mad at you because you didn't tell her is a hell of a way to find out that maybe you should have...