Slažu se kao pas i mačka :)
The verb "slagati se" imperf.(with first "a" being long) /"složiti se" perf.  = to agree * can have a range of different meanings in Serbian and we're going to discuss them today, because I'll need it for my next lesson about Serbian history.

The simple present tense conjugations of the verb SLAGATI:
(Sg) Slažem se - slažeš se - slaže se  (Pl) Slažemo se - slažete se - slažu se 

The past tense verb forms 
- Imperfective aspect
( _ denotes the auxiliary "to be" which shows which person is the sentence referring to)
(Sg) M slagao _ se, F slagala _ se, N slagalo _  se
(Pl) M slagali _ se , F slagale _ se, N slagala _ se
- Perfective aspect:

( _ denotes the auxiliary "to be" which shows which person is the sentence referring to)
(Sg) M složio _ se, F složila _ se, N složilo _  se
(Pl) M složili _ se , F složile _ se, N složila _ se


The simple future forms:
- Imperfective aspect
(Sg) Slagaću se - slagaćeš se - slagaće se
(Pl) Slagaćemo se - slagaćete se - slagaće se
Perfective aspect:
(Sg) Složiću se - složićeš se - složiće se
(Pl) Složićemo se - složićeš se - složiće se

* You might also find the word "slagati" which means "to lie", but the stress pattern is different (with the first  "a" being short) and there is no reflexive " se".
** You might also find the word "slagati" with the same  stress pattern as "slagati se" (to agree), but without the reflexive "se". In that case, the verb "slagati" means "to stack things" or " to put things in order"