Sup,
If I get your drift, you're asking if you can sign each other off in order to log flight time. You're asking about time building, and you need to be building experience. It's not the same thing. The difference between the two can be as little as having a game plan and going out to work the airplane, intead of simply riding to log time.
If you intend to operate under simulated instrument flight with a safety pilot, the fact that either of you holds a flight instructor certificate isn't relevant. You can both log pilot in command time at the same time, regardless of your instructor certificates.
In order to do this, the safety pilot must be the acting pilot in command, and can log the time as PIC under 61.51(e)(1)(iii). He or she may also log time as PIC when acting as an authorized instructor, under 61.51(e)(3).
If you are rated in the airplane (category and class), you may log all time spent as sole manipulator of the controls as pilot in command under 61.51(e)(1)(i). You may elect to log instruction received, but you do not need to do so. If the instruction is toward a certificate or rating, it must be logged. If your friend is indeed providing instruction to you, then he must endorse your logbook or training record. However, you may still log the time as pilot in command if rated in the airplane.
Nobody is going to frown on receiving instruction, but you sound as though you're looking for a loophole to log time, rather than intending to receive bonifide instruction. There is nothing wrong with being a flight instructor and receiving instruction; nobody will fault you for this. You may be faulted for not knowing the regulations which you are required to teach, however. Therefore, now is a good time to dig into your books and review Part 61. Good luck!
