To understand the annotations here are some definitions that we can find on the book  the bass in tango by Ignacio Varchausky.

Fraseo cuadrado: Performing an expressive passage (that means a melodic passage) using the written rhythm without modifying the fraseo or the tempo.10 

Fraseo pelotita: A form of phrasing that involves speeding up the phrase toward the target note in imitation of a increasingly rapid bouncing of a dropped ball.11 


Here a picture to understand better.



Fraseo básico: A kind of phrasing that modifies the written rhythm but respects the 1st and 3rd beats of the bar as points of arrival. 12 

Arrastre/Arrastrado/Arrastrando: The effect produced by anticipating a note or chord with notes of indeterminate pitch and length that finish abruptly upon arriving at the pitch and length of the written note. This effect provokes a particular sensation in the movement of the rhythm, melodically and hermonically, since adds an amorphous anticipation to the precise "shape" of an articulation. Depending on the instruments, it is generally executed as a combination of glissandi, chords, clusters or ascending chromatics with a slight crescendo. 13


Pesante:  Is a tango accompaniment  that bgives the music a calm and less intense feeling. Most of the time it is used to accompany a soloist. 14 


Strapatta: Percussive effect made by hitting the strings of the double bass with the bow and the palm of the left hand at the same time. 15 


3.3.2: Its name describes how the eighth notes are grouped, according to the accents in the measure. 16 


Yumba: Its name is taken from the onomatopoeic sound it makes when played: “YUM-BA, YUM-BA” the “YUM” syllable on the strong beats and the “BA” syllable on the weak beats. This effect comes from Osvaldo Pugliese's orchestra where it was used as marking time model. 17