It is possible to have more than one constriction gesture, that is, it's possible to narrow the vocal tract at two or more places at the same time. Multiple articulations are often classified as double articulations and secondary articulations on the basis of whether the two constrictions are equal in degree. Double articulations without their own symbol can be transcribed by giving the symbols for each articulation and putting the tie symbol above them. Secondary articulations are often closely related to vowels.
English consonants can have secondary articulations through assimilation to a neighbouring vowel.
It is possible for languages to contrast consonants with a secondary articulation and consonants without. So does Gaelic. Arabic contrasts pharyngealized and non-pharyngealized consonants. These can be seen as simple postalveolar fricatives with palatalization as a secondary articulation.