A method of amplifying a nucleic acid target region, the method comprising: contacting a target nucleic acid comprising the target region with a first amplification oligomer comprising (a) a target-binding priming segment substantially complementary to a 3'-end of the target region; and (b) a first heterologous displacer tag located 5' to T1; said contacting comprising conditions whereby the target nucleic acid serves as a template for extension from the first amplification oligomer to produce a first amplification product comprising T1 and D1; a second amplification oligomer comprising a target-binding segment T2 substantially complementary to a region of the first amplicon that is the complement of a 5'-end of the target region, and wherein said contacting further comprises conditions whereby the first amplicon serves as a template to produce a second amplicon comprising segments cT1 and cD1, complementary to T1 and D1, respectively; a third amplification oligomer comprising target-binding priming segment T1 p having a nucleotide sequence substantially corresponding to T1, or substantially corresponding to the complement of a second amplicon target sequence cT1' near or overlapping with cT1 and situated 5' to cD1; and a fourth amplification oligomer comprising a displacer priming segment D1 p having a nucleotide sequence substantially corresponding to D1; wherein said contacting further comprises conditions whereby the second amplicon serves as a template for extension from both the third and fourth amplification oligomers, wherein extension of T1 p from a T1 p:cT1/cT1' hybrid produces a third amplicon, and wherein extension of D1 p from a D1 p:cD1 hybrid produces a fourth amplicon while displacing the third amplicon. contacting a target nucleic acid comprising the target region with a first amplification oligomer comprising (a) a target-binding priming segment substantially complementary to a 3'-end of the target region; and (b) a first heterologous displacer tag located 5' to T1; said contacting comprising conditions whereby the target nucleic acid serves as a template for extension from the first amplification oligomer to produce a first amplification product comprising T1 and D1; a second amplification oligomer comprising a target-binding segment T2 substantially complementary to a region of the first amplicon that is the complement of a 5'-end of the target region, and wherein said contacting further comprises conditions whereby the first amplicon serves as a template to produce a second amplicon comprising segments cT1 and cD1, complementary to T1 and D1, respectively; a third amplification oligomer comprising target-binding priming segment T1 p having a nucleotide sequence substantially corresponding to T1, or substantially corresponding to the complement of a second amplicon target sequence cT1' near or overlapping with cT1 and situated 5' to cD1; and a fourth amplification oligomer comprising a displacer priming segment D1 p having a nucleotide sequence substantially corresponding to D1; wherein said contacting further comprises conditions whereby the second amplicon serves as a template for extension from both the third and fourth amplification oligomers, wherein extension of T1 p from a T1 p:cT1/cT1' hybrid produces a third amplicon, and wherein extension of D1 p from a D1 p:cD1 hybrid produces a fourth amplicon while displacing the third amplicon. a first amplification oligomer comprising (a) a target-binding priming segment substantially complementary to a 3'-end of the target region; and (b) a first heterologous displacer tag located 5' to T1; said contacting comprising conditions whereby the target nucleic acid serves as a template for extension from the first amplification oligomer to produce a first amplification product comprising T1 and D1; (a) a target-binding priming segment substantially complementary to a 3'-end of the target region; and (b) a first heterologous displacer tag located 5' to T1; said contacting comprising conditions whereby the target nucleic acid serves as a template for extension from the first amplification oligomer to produce a first amplification product comprising T1 and D1; a second amplification oligomer comprising a target-binding segment T2 substantially complementary to a region of the first amplicon that is the complement of a 5'-end of the target region, and wherein said contacting further comprises conditions whereby the first amplicon serves as a template to produce a second amplicon comprising segments cT1 and cD1, complementary to T1 and D1, respectively; a third amplification oligomer comprising target-binding priming segment T1 p having a nucleotide sequence substantially corresponding to T1, or substantially corresponding to the complement of a second amplicon target sequence cT1' near or overlapping with cT1 and situated 5' to cD1; and a fourth amplification oligomer comprising a displacer priming segment D1 p having a nucleotide sequence substantially corresponding to D1; wherein said contacting further comprises conditions whereby the second amplicon serves as a template for extension from both the third and fourth amplification oligomers, wherein extension of T1 p from a T1 p:cT1/cT1' hybrid produces a third amplicon, and wherein extension of D1 p from a D1 p:cD1 hybrid produces a fourth amplicon while displacing the third amplicon.