Takrir means repetition and is a special characteristic of ر (ra). The tongue tip has a natural tendency to vibrate or repeat contact while producing ra.
Important caution: knowing this quality should prevent excessive trilling that turns one ra into an apparent sequence of several ra sounds. In «رَبّ» or «مَرْيَم», maintain the normal, prescribed consonant rather than an exaggerated series of rolls.
The remedy is not to stiffen the tongue until ra loses its identity. Correct recitation preserves the letter's natural articulation while avoiding superfluous repetition.